Is a Complaint Enough to Arrest? Gender Violence and Sexual Assault

An analysis of the constitutional, statutory and case-law requirements for the precautionary deprivation of liberty and of the (in)sufficiency of a complaint —with or without a request for a protection order— as a precondition for the arrest of the person reported. A legal-doctrinal study · Criminal Procedure and Criminal Law · June 2026.

Abstract

Keywords: police custody; personal liberty; gender-based violence; sexual assault; criminal complaint; protection order; proportionality; VioGén System; unlawful detention.

I. Introduction and Scope of the Study

Police custody is, together with pre-trial detention, the most intense interference by the State that the legal order permits against the liberty of someone who is still presumed innocent. Precisely for that reason, its regime is not one of free appraisal by the authority: it is bounded by the Constitution and by statute with a rigour that the legal practitioner does not always carry across into practice. In the field of gender-based violence and of offences against sexual freedom, that tension is sharpened. The legitimate social demand for an immediate and effective response to these forms of violence coexists with the equally non-negotiable guarantee that no one shall be deprived of liberty save in the cases and in the manner prescribed by law (art. 489 LECrim).

This study addresses a specific question, frequently posed both by legal professionals and by police officers themselves: is the mere filing of a complaint for gender-based violence or for sexual assault —whether or not the complainant requests a protection measure— a sufficient precondition for the police custody of the person reported? The question is not rhetorical: on its answer depend the lawfulness of thousands of police actions each year, the integrity of the safeguards owed to the person under investigation and, on the reverse side, the effectiveness of the protection of the victim.

To answer it rigorously it is necessary to work through, first, the constitutional status of personal liberty and the statutory regime of arrest (sections II to IV); next, the specific normative framework of gender-based violence and of the sexual offences, with its police protocols (section V); and, finally, to project one onto the other in order to resolve the core problem and its consequences (sections VI and VII). The thesis maintained here can be anticipated: a complaint is a condition that sets the investigation in motion, but it is not, on its own, a sufficient basis to arrest; and whether or not a protection order is requested is, for these purposes, legally immaterial.

II. Personal Liberty as a Fundamental Right and Arrest as an Interference

Article 17.1 of the Constitution proclaims that «everyone has the right to liberty and security» and that «no one may be deprived of their liberty save in compliance with the provisions of this article and in the cases and in the manner laid down by law». Arrest is therefore a narrowly defined exception to a fundamental right and, as such, must be interpreted restrictively. The provision itself sets the insurmountable time limit: preventive custody «may not last longer than the time strictly necessary to carry out the inquiries aimed at clarifying the facts» and, in any event, within the maximum period of seventy-two hours the detainee must be released or brought before the judicial authority (art. 17.2 CE).¹

This domestic standard is reinforced by the international law of human rights. Article 5 of the European Convention on Human Rights guarantees liberty and security and permits arrest only where there are «reasonable grounds» for suspecting that an offence has been committed (art. 5.1.c ECHR); and Article 9 of the International Covenant on Civil and Political Rights prohibits any «arbitrary» arrest. The European Court of Human Rights has clarified that the «reasonable suspicion» that legitimises an arrest presupposes the existence of facts or information that would satisfy an objective observer that the person may have committed the offence.²

From this framework a first capital consequence already follows for the object of this study: the legitimacy of an arrest is not measured by the nominal gravity of the accusation or by the alarm that a fact may generate, but by the presence of an objective basis —indications— and by its necessity for a constitutionally legitimate purpose. Arrest is not an act of anticipated reproach, nor a measure to satisfy the victim or public opinion: it is a precautionary instrument at the service of the proceedings and of protection against a present risk.

III. The Statutory Regime of Arrest in the Criminal Procedure Act

3.1. The principle of legality

Article 489 LECrim states the governing rule: «no Spaniard or foreigner may be arrested save in the cases and in the manner prescribed by the laws». Arrest is, therefore, a numerus clausus: it is permissible only in the situations defined by statute and with observance of the prescribed formalities. Outside them, the deprivation of liberty becomes unlawful, with the criminal consequences examined in section VII.

3.2. Arrest by private persons and flagrante delicto (art. 490)

Article 490 LECrim empowers —but does not oblige— «any person» to arrest in defined situations: anyone attempting to commit an offence at the moment of going to commit it; the offender caught in fraganti; anyone who escapes from a penal establishment or during transfer; the accused or convicted person who is in default of appearance, among others. The common feature is flagrante delicto or a situation of equivalent obviousness: the subject is caught in the commission of the offence, or immediately afterwards, so that direct perception of the facts removes all reasonable doubt as to participation. Flagrante delicto is, par excellence, the basis that justifies the most immediate intervention, including in the field with which we are concerned.

3.3. Arrest by the authority and the judicial police (art. 492)

Article 492 LECrim imposes on «the authority or agent of the judicial police» a duty to arrest: (1.º) anyone who is in one of the situations of Article 490; (2.º) the person accused of an offence carrying a penalty higher than that of correctional imprisonment; (3.º) the person accused of an offence carrying a lower penalty where their record or the circumstances of the act give reason to presume that they will not appear, unless they post bail; and, above all, (4.º) anyone in respect of whom, even though not formally accused, the two conditions examined below are met.³

3.4. The substantive precondition: «reasonable grounds»

Article 492.4.º LECrim condenses the substantive core of any police arrest. It requires that the authority or the agent have: (i) «reasonable grounds to believe in the existence of a fact bearing the features of an offence»; and (ii) «sufficient grounds to believe that the person they intend to arrest took part in it». These are the two pillars of the institution: an indication as to the act (that an offence exists) and an indication as to authorship (that this person took part). Legal scholarship identifies them with the fumus boni iuris proper to every precautionary measure; the case law, with the «reasonable suspicion» of the Convention. In both cases an objective and verifiable basis is required, not the officer's inner conviction or the mere accusation made by a third party.

The intensity of those indications that may be demanded is, moreover, gradable according to the interference: scholarship and case law have come to distinguish a minimum threshold in arrest for flagrante delicto, an intermediate one in preventive police custody, and a heightened one in pre-trial detention. The more serious the measure, the greater the solidity of the underlying indications must be. The decisive point is that, in every case, something more than the mere assertion that an offence has been committed is required: a factual basis that rationally sustains it is required.

3.5. The limit of petty offences (art. 495)

Article 495 LECrim prohibits arrest «for the simple commission of petty offences, unless the alleged perpetrator has no known domicile and does not post sufficient bail». The rule has practical impact in our field: most of the gender-violence offence types —occasional ill-treatment under art. 153 CP, habitual ill-treatment under art. 173.2, injuries, threats or coercion— are less serious or serious offences, fully susceptible to arrest; but certain conduct, such as the minor insult or unjust vexation of art. 173.4 CP, is a petty offence and is therefore subject to the severe restriction of art. 495. The same may be said of sexual assault, which never constitutes a petty offence.

3.6. Time limits

Two time limits coexist. Article 496 LECrim requires the person making the arrest to release the detainee or hand them over to the nearest judicial authority within the following twenty-four hours; and Article 17.2 CE sets the absolute cap of seventy-two hours for preventive custody, reiterated in art. 520.1 LECrim. Both periods are maximums: the arrest must be lifted as soon as its basis disappears, that is, as soon as the inquiries have concluded or the grounds that justified it fall away.

3.7. The rights of the detainee and habeas corpus

Arrest immediately triggers the bundle of safeguards of Article 520 LECrim: information —in writing and in comprehensible language— as to the imputed facts and the reasons for the arrest, as well as the rights to which the detainee is entitled; the right to remain silent and not to incriminate oneself; the assistance of a lawyer, including in police proceedings; the designation of a person to whom the arrest is to be communicated; the assistance of an interpreter; a medical examination; and access to the essential elements of the proceedings in order to challenge the lawfulness of the arrest.⁴ The system is rounded off by the safeguard of habeas corpus (art. 17.4 CE and Organic Act 6/1984), a summary procedure for obtaining the immediate bringing before a judge of anyone unlawfully detained. This last point is significant: review of the regularity of the arrest is neither deferred nor merely theoretical, but immediate and judicial.

IV. Guiding Principles and the Purposes of Arrest

4.1. The proportionality test

Onto the foregoing statutory framework is projected a set of principles of constitutional rank that condition not only the existence of the precondition, but the appropriateness of ordering the arrest. Arrest is a precautionary measure and, like any interference with a fundamental right, is subject to the proportionality test required by the Constitutional Court: suitability (that the measure serves the purpose pursued), necessity (that there is no less harmful, equally effective alternative) and proportionality in the strict sense (that more benefits for the general interest derive from the sacrifice of the right than detriments to the conflicting interest).⁵

From that test derive the exceptionality of arrest —it is not the ordinary response to the notitia criminis, but the one reserved for cases in which it is indispensable— and its restrictive interpretation, as a narrowly defined exception to the right to liberty.⁶ Arrest is, moreover, instrumental: it has no value in itself, only by reference to the purposes it serves; hence, where those purposes can be achieved by a less burdensome means —chiefly, the summons—, it ceases to be necessary and, therefore, proportionate.

It should be stressed that the duty to arrest under Article 492 LECrim is not a blind automatism. The verb «shall be under a duty to arrest» is read in the light of the Constitution: the authority must assess, case by case, whether the substantive preconditions are met, whether the measure pursues a legitimate purpose and whether it is necessary. Otherwise, the provision would authorise disproportionate arrests, which no constitutional test permits.

4.2. The constitutionally legitimate purposes (in the face of the silence of art. 492)

Unlike pre-trial detention, whose purposes are today listed in art. 503 LECrim, art. 492 does not specify what arrest is for. That silence is not a blank authorisation: by its precautionary nature, arrest is justified only by legitimate purposes, which the constitutional case law has distilled in connection with pre-trial detention and which are transferable —with a lighter threshold, since arrest is a less intense and briefer measure— to the police deprivation of liberty.⁷

There are thus four purposes that can legitimise an arrest:

• (a) To secure the submission of the person under investigation to the proceedings, averting the risk of flight.
• (b) To preserve the sources of evidence, preventing their concealment, alteration or destruction and allowing urgent investigative steps.
• (c) To prevent the repetition of the offence and to stop the completion or continuation of the offence in progress.
• (d) To protect the victim from a present danger —a purpose of particular weight in gender-based violence, which the law expressly provides for in the case of pre-trial detention (art. 503.1.3.º c LECrim)—.

To these substantive purposes is added the instrumental purpose proper to arrest: the bringing before a judge within the maximum period of seventy-two hours, so that the judge may review the measure and rule on the person's situation and, where appropriate, on the protection order. But this purpose is not autonomous: it presupposes that one of the foregoing is present. Where appearance before the judge can be secured by summons (art. 796 LECrim), the bringing before the judge does not require a prior arrest.

Excluded, on the other hand, are purposes unrelated to precaution: the anticipation of punishment —arrest is neither a penalty nor an advance reproach—, the appeasement of social alarm or media demand —content proper to general deterrence, which the Constitutional Court has rejected as a basis for the precautionary deprivation of liberty— and pressure on the person under investigation to obtain their confession or cooperation.⁸

4.3. The requirements for the presence of each purpose

Having identified the purposes, it remains to specify when each may be regarded as present. The common requirement, of constitutional root, is twofold: the assessment must be specific and individualised —supported by verifiable circumstances and reflected in the police report—, and it can never be inferred from the gravity of the imputed act alone; in case of doubt, the favor libertatis applies.

• (a) Risk of flight. Its assessment looks to the community ties of the person under investigation —domicile, family, work, social bonds—, to their means of evading justice (resources, connections abroad) and to their prior procedural conduct (failures to appear, defaults, use of a false identity). The gravity of the penalty is a relevant but, by itself, insufficient factor: the risk cannot be inferred automatically from it, but from the set of specific circumstances.⁹
• (b) Securing the evidence. It requires sources of evidence not yet secured and a real capacity or willingness to manipulate them —altering traces, influencing witnesses or the victim, alerting co-perpetrators—. It falls away where the essential evidence is already documented (a medical report) and cannot be inferred from the legitimate exercise of the right of defence: the silence of the person under investigation is never an indication of obstruction.
• (c) Prevention of repetition and cessation of the offence. It rests on objective data of the probability of fresh acts: prior records and complaints, earlier breaches, signs of escalation in frequency or intensity, the continuation of cohabitation or of the conflict, the access of the person under investigation to the victim or to weapons. In flagrante delicto it comprises the immediate need to bring the assault in progress to an end.
• (d) Protection of the victim. It requires a present and specific risk to her life, integrity or liberty —not a mere hypothesis—, arising from the proximity or access of the aggressor, from threats, from the use or availability of weapons, from an escalation or from prior breaches, of such magnitude as to call for immediate separation without being able to await the appearance before the court. It is the purpose in which the police assessment of risk (VioGén System; cf. 5.5) deploys its utility, as an instrument for the appraisal —not the substitution— of the legal judgment of proportionality.

4.4. A special treatment for gender-based violence? Hierarchy of norms and proportionality

It may then be asked whether gender-based violence and sexual assault are subject to a different, more severe arrest regime. The answer requires ordering three normative levels of decreasing rank and specifying what each may do in respect of arrest.

First level —the Constitution. The proportionality test and the reservation of statute (arts. 9.3, 17.1, 53.1 and 81.1 CE) constitute the ceiling of the system. No lower-ranking rule may lower the safeguards or turn arrest into something automatic; the test cannot be derogated from by statute or by instruction.

Second level —the gender-violence statutes. Organic Act 1/2004 and the reforms of the LECrim (arts. 503.1.3.º c, 544 bis and 544 ter) have statutory rank and, for that reason, may afford a legitimate special treatment: they are, precisely, the law that the reservation in art. 17 CE calls for, and they have expressly identified and weighed the purpose of protecting the victim, in addition to creating specialised bodies and procedures. But that treatment operates within the constitutional test and is subject to its supervision: they cannot order a disproportionate or automatic arrest, and the Constitutional Court itself has verified its proportionality —thus, in upholding the constitutionality of the differentiated criminal treatment of art. 153.1 CP—.¹⁰

Third level —the VioGén instruments. Instruction 1/2025 SES and the VPR/VPER forms are administrative instructions (art. 6 of Act 40/2015), of sub-statutory rank and internal effect (ad intra): they bind officers in the organisation of protection, but they create no obligations and restrict no rights of citizens (ad extra).¹¹ From this two capital consequences follow. First: a VioGén risk level —even «high» or «extreme»— is not a basis for arrest and cannot lower the constitutional threshold; it is, at most, one element in assessing the purpose of protecting the victim (4.3.d), which remains subject to the proportionality test. Second: the «mandatory measures» associated with each level require the deployment of police protection measures (surveillance, contact, accompaniment), not the carrying out of an arrest that lacks a statutory basis. Reading a risk level as an automatic arrest would breach the reservation of statute and the hierarchy of norms (art. 9.3 CE) and could constitute unlawful detention.

In sum: gender-based violence receives a special treatment at the statutory level —which heightens the purpose of protecting the victim and articulates dedicated procedures—, but not at the level of the constitutional test, which is identical for every offence; and the VioGén instruments, by their rank, neither alter that test nor add preconditions to arrest: they inform it, they do not replace it.

4.5. The bearing of the VioGén risk level on the reasoning of the police report

The non-automatic character of arrest is projected onto the police report. Although police custody is not documented in a reasoned order like judicial decisions, the police report must reflect the circumstances that sustain the indications and the precautionary purpose, for it constitutes the basis on which the Public Prosecutor's Office and the court exercise immediate review of the measure —the bringing before the judge and the hearing of art. 544 ter— and on which, where appropriate, a habeas corpus is decided. An arrest without express support in the police report is hardly amenable to review and, for that reason, suspect of arbitrariness.

At this point, the Police Risk Assessment (VPR) occupies a precise and limited place. It is a structured instrument supporting the appraisal of the purpose of protecting the victim (4.3.d): it orders and objectivises the judgment about the danger of repetition, but it is neither a basis for arrest nor a substitute for reasoning.¹² Its reflection in the police report must therefore observe several rules.

First. The risk level is a conclusion, not a reasoning. Recording «high risk, an arrest is carried out» is only an apparent reasoning; the police report must set out the specific facts that ground that level —threats, the use or availability of weapons, escalation, prior breaches, etc.— and connect them with the precautionary purpose and with the necessity of the arrest. It is the factual basis, and not the label on the form, that justifies the measure.

Second. The VioGén level measures the risk to the victim (purpose d), but says little about the other purposes. A «low» level does not preclude arrest where a risk of flight or of destruction of evidence is present (purposes a and b); and, conversely, a «high» level does not dispense with the judgment of necessity and proportionality, nor does it make arrest mandatory. The risk datum is integrated with community ties, the situation of the evidence and procedural conduct; it does not displace them.

Third. The standardised nature of the VPR —a questionnaire with weighted indicators— assists, but cannot displace the individualised judgment. To entrust the decision to arrest to the automatism of the form would amount to «administrativising» a deprivation of liberty and to attributing to a management instrument an effect that, by its rank (4.4), it cannot produce.¹³

Properly understood, on the other hand, the risk assessment is an ally of legality: a police report that articulates indications, precautionary purpose and necessity —relying on the VPR as one element, and not as an alibi— serves at once the protection of the victim and the legal soundness of the arrest in the face of its subsequent judicial review.

4.6. Synthesis: a decision scheme

The following scheme synthesises the decision-making itinerary that results from all the foregoing. Each filter must be passed for the arrest to be legitimate; the failure of any one of them leads towards a less harmful response —notably, the summons— or towards the unlawfulness of the arrest.

V. The Specific Framework: Gender-Based Violence and Sexual Assault

5.1. Organic Act 1/2004 and the concept of gender-based violence

Organic Act 1/2004 of 28 December, on Comprehensive Protection Measures against Gender Violence, defines it as the violence which, «as a manifestation of discrimination, of the situation of inequality and of the power relations of men over women», is exercised over women by those who are or have been their spouses or are or have been linked to them by analogous relationships of affection, even without cohabitation. The Act created the Courts for Violence against Women (art. 87 ter LOPJ) and articulated comprehensive protection —criminal, civil, welfare and institutional—, but it did not alter the general regime of arrest: this continues to be governed by the LECrim and by the principles already set out.

5.2. The reform of the sexual offences: recent trajectory (2021–2026)

Offences against sexual freedom have seen, in recent years, an intense succession of reforms which it is worth situating. The first, Organic Act 8/2021 of 4 June, on the comprehensive protection of children and adolescents against violence, reinforced the protection of minors and, in what concerns us here, postponed the running of the limitation period for sexual offences committed against them, which does not begin to run until the victim turns thirty-five (art. 132 CP).¹⁴

The second, Organic Act 10/2022 of 6 September, on the comprehensive guarantee of sexual freedom —the «only yes means yes» Act—, reordered the matter around the axis of consent: it abolished the distinction between assault and abuse and unified under the offence of sexual assault every attack on sexual freedom carried out without the consent of the other person, defined as the free expression of the will (art. 178.1 CP).

The third, Organic Act 4/2023 of 27 April, corrected the unintended effects of the previous one —the reductions in penalty arising from the new ranges— without abandoning the consent model: it reintroduced, as an aggravated modality of sexual assault and of rape, its commission with violence or intimidation or against a victim whose will has been nullified, restoring more severe penalty frameworks (arts. 178 to 180 CP).¹⁵

The most recent is still in the legislative pipeline: the Bill for an Organic Act on the protection of minors in digital environments —approved by the Council of Ministers on 25 March 2025 and admitted for processing by the Congress on 10 September 2025— provides for amending the Criminal Code to criminalise deepfakes of a sexual or seriously degrading content —as an offence against moral integrity and in respect of any person— and to reinforce the response to grooming.¹⁶

For the purposes of this study, two consequences matter. First: following the unification of 2022, every attack on sexual freedom without consent is, at the very least, a less serious or serious offence —never a petty offence—, susceptible by its nature to arrest where the general preconditions are met. Second, and capital: none of these reforms has altered the regime of arrest, which continues to be governed by the LECrim and by the constitutional test already examined; they have modified the definition of the offence, the penalty, limitation and, in part, prosecutability, but not the preconditions or the purposes of the precautionary deprivation of liberty.

5.3. The prosecutability regime: public and semi-public offences

A technical distinction is unavoidable here. The core gender-violence offences (arts. 153, 173.2, 148, 169 to 172 CP, among others) are public offences, prosecutable of the court's own motion: once known, the Public Prosecutor's Office and the courts must act independently of the will of the victim, who can neither «withdraw» the complaint nor grant an effective pardon. Sexual assault, by contrast, is a semi-public offence: art. 191 CP requires, in order to proceed, a complaint by the aggrieved person, by their legal representative or a prosecution brought by the Public Prosecutor's Office; the latter's complaint suffices where the victim is a minor, a person with a disability in need of special protection or a defenceless person.¹⁷

This difference has a precise reading in the problem with which we are concerned. In public offences, the absence of a complaint or of a request for protection by the victim does not prevent action; in semi-public offences, the complaint is a precondition of the proceedings, but —as will be seen— it still does not, on its own, constitute a basis for arrest.

5.4. The protection order (art. 544 ter LECrim) and the precautionary measures

The protection order, introduced by Act 27/2003 and regulated in Article 544 ter LECrim, is a judicial decision which, where there are well-founded indications of an offence of gender-based or domestic violence and an objective situation of risk to the victim, concentrates in a single order criminal measures (a restraining order, a prohibition on communication and on residence under art. 544 bis), civil measures and social-welfare measures. It is granted following an urgent hearing, which must be held within a maximum period of seventy-two hours, with the participation of the Public Prosecutor's Office, the victim and the alleged aggressor assisted by a lawyer. It may be requested by the victim or their relatives, but it may also be sought by the Public Prosecutor's Office and, where appropriate, granted by the judge in the exercise of their powers.

Two points matter now. First: the protection order is issued by the judge, not by the police. The police role is to receive the request, document it in the police report and forward it urgently to the court; it is not for them to «grant» protection by way of an arrest. Second: the request for an order and the arrest are distinct institutions, with distinct preconditions. Whether or not the victim requests a protection order adds nothing to, and subtracts nothing from, the presence of the «reasonable grounds» of art. 492.4.º LECrim.

5.5. The police protocol and the VioGén System

Police action is ordered by means of the Protocol of action of the Security Forces and Corps and of coordination with the judicial bodies for the protection of victims of domestic and gender violence, and by means of the Comprehensive Monitoring System in cases of Gender Violence (VioGén System). Under the Protocol, the alleged aggressor is arrested and brought before a judge «where the nature of the facts or the situation of risk so advise», and notably in cases of flagrante delicto and of wilful breach of a restraining measure already granted, which entails an objective increase in risk and the immediate arrest of the offender (art. 468 CP).¹⁸

The VioGén System incorporates a risk-assessment instrument: the Police Risk Assessment (VPR) at the moment of the first intervention and the successive Police Risk Evolution Assessments (VPER), which classify the case into four levels (low, medium, high and extreme), to each of which mandatory protection measures are attached. Its regime in force is Instruction 1/2025 of the State Secretariat for Security, which rolled out the VioGén-2 System and repealed the previous Instruction 4/2019.¹⁹

From this design it is worth highlighting a decisive feature: the assessment of risk and the police protection measures are not conditioned on the prior filing of a complaint. Indeed, where a victim in a situation of possible lack of protection expresses a refusal to report, the so-called «Protocol Zero» is activated, aimed at gathering information and minimising risk even without a complaint.²⁰

VI. The Core of the Problem: Is a Complaint Enough to Arrest?

6.1. The complaint as notitia criminis

A complaint is the act by which the possible commission of an offence is brought to the attention of the authority (arts. 259 et seq. LECrim). Its proper effect is to set the investigation in motion: it obliges the police and the judge to check the facts, to carry out the urgent investigative steps and to document them in the police report. A complaint is, in short, the trigger of the proceedings, not their anticipated conclusion. From it arises a duty to inquire; it does not give rise, without more, to a duty —or even an unconditional power— to arrest.

6.2. The insufficiency of the mere complaint

The answer to the question that structures this study is, therefore, in the negative: the mere filing of a complaint for gender-based violence or for sexual assault is not, on its own, a sufficient precondition for the police custody of the person reported. And this is because the complaint, considered in isolation, does not satisfy the substantive precondition of Article 492.4.º LECrim. That provision does not require a complaint, but «reasonable grounds» to believe in the existence of an offence and in the participation of the suspect. A complaint may contribute to forming those grounds —and frequently does, especially when accompanied by objective corroboration—, but it is not equivalent to them.

The difference is qualitative. It is one thing for the victim's statement to carry, in these offences, evidential weight of the first order —to the point of being capable of sustaining, if it meets certain guarantees, a conviction—; and quite another for its mere formal existence, before any assessment, to be automatically transmuted into the precondition for a deprivation of liberty. What the legal order demands is an assessment: the officer drawing up the police report must weigh the plausibility and coherence of the account, its corroboration by peripheral data (injuries, medical reports, witnesses, the state of the victim, prior records, messages), the persistence of the incrimination and the presence of a risk. From that assessment, and not from the complaint as such, arises —or does not— the underlying support that art. 492 requires.

To this is added the filter of proportionality (section IV). Even where indications are present, arrest is warranted only if it is necessary for a precautionary purpose: to secure appearance, to prevent repetition, to protect the victim from a present danger. Where that purpose can be satisfied by summoning the person under investigation —because, for example, the act is of little magnitude, with no appreciable risk and with a person reported who is fully identified and has community ties—, arrest is unnecessary and therefore improper. As the Public Prosecutor's Office itself has warned, what is not proportionate is to carry out an «automatic» arrest.²¹

6.3. The irrelevance of the request for a protection order

The second part of the question —«whether or not the complainant requests a protection measure»— admits of a clear answer: the request for a protection order is, for the purposes of arrest, legally immaterial. It is neither a necessary nor a sufficient precondition of the deprivation of liberty.

It is not sufficient. The victim's requesting a protection order does not, in itself, authorise the police to arrest. The order is granted by the judge following the hearing under art. 544 ter LECrim; until that decision is taken, the situation of the person reported is governed by the preconditions for arrest, not by the content of a request not yet resolved. The petition for protection expresses a will to obtain protection that is worthy of attention, but it does not create ex novo the «reasonable grounds» that art. 492 calls for.

It is not necessary. Conversely, the victim's not requesting any measure —or even being reluctant to report— does not preclude arrest where its preconditions are met. In the case of public offences, prosecution does not depend on the will of the victim; in flagrante delicto, any person —and, all the more so, the police— may arrest (art. 490); and the police assessment of risk, as has been seen, operates independently of the complaint (Protocol Zero). Indeed, the protection order itself may be sought by the Public Prosecutor's Office and adopted by the judge without the need for an express request from the victim. Protection, therefore, does not hinge on a formal request, nor does arrest on its presence or absence.

In short, neither the complaint nor the request for protection is, separately or together, a basis for arrest. The basis is always provided by the presence of objective indications —flagrante delicto or «reasonable grounds»— subject to the judgment of necessity and proportionality.

6.4. Corroborated indications without a precautionary purpose: fumus boni iuris versus periculum

It is now appropriate to confront a situation of the greatest practical relevance, and perhaps the most delicate: that in which the complaint appears corroborated —the victim produces a medical or psychological report, displays a bruise or presents a minor injury— but no precautionary purpose is present. The person reported is fully identified, has a domicile and community ties, there is no risk of flight or any indication that they intend to evade the action of justice, the essential source of evidence is already secured and no present risk of repetition against the victim is discernible. Is it then enough, in order to arrest, for the indications to be solid?

The answer requires distinguishing the two axes on which every precautionary measure, and therefore arrest, rests. The first is the fumus boni iuris, or appearance of good right: the probability, supported by indications, that an offence exists and that the suspect took part in it. The second is the periculum, or procedural danger: the risk that the pendency of the proceedings projects onto their purposes —danger of flight, of repetition of the offence (notably, the risk to the victim) or of destruction or concealment of evidence—.²² They are cumulative and independent requirements: the presence of one does not presume that of the other.

From that distinction follows the key to the problem. Corroboration of the complaint operates on the first axis: it reinforces the fumus, makes the imputation more plausible and consolidates the «reasonable grounds» of art. 492.4.º LECrim. But it does not bear on the second: however solid the appearance of an offence, it does not by itself create a procedural danger where there is none. Confusing the two planes —inferring the need to arrest from the strength of the evidence— is the most widespread conceptual error in this field, for it turns arrest into an advance penalty proportionate to the force of the incrimination, when its only constitutional justification is precautionary.

There is, moreover, a paradox that it is worth making explicit. The medical report or the documentation of the injury, far from reinforcing the need to arrest, weakens it in one precise respect: it secures the source of evidence. Once the harmful result is documented, the risk of its disappearance falls away, so that the precautionary purpose of securing the evidence —one of those that could legitimise the deprivation of liberty— precisely ceases to be present in respect of that element.

For all these reasons, where the indications are solid but every precautionary purpose is lacking, arrest is not necessary and therefore becomes disproportionate: it would be a deprivation of liberty with no precautionary function to serve, incompatible with the instrumental character of the measure and with the presumption of innocence. The response the legal order itself provides is then not to arrest, but to summons: art. 796 LECrim requires the judicial police to summons the person reported to appear before the duty court —or, in gender-based violence, before the Court for Violence against Women on the nearest working day— «where no arrest has been made».²³ The summons secures appearance and the holding of the expedited trial or of the art. 544 ter hearing without sacrificing the liberty of someone who poses no procedural danger whatsoever.

This conclusion calls, nonetheless, for two cautions. The first, of a doctrinal order: since the regulation of arrest does not list its purposes —unlike pre-trial detention (art. 503 LECrim)—, a more automatic reading of the «duty to arrest» of art. 492 has been advocated; but the precautionary nature of the measure and the proportionality test impose, despite the statutory silence, the requirement of a purpose.²⁴ The second, of a practical order and proper to our field: in gender-based violence the risk to the victim is an autonomous, frequent and delicately assessed precautionary purpose. An injury, even a minor one, may be the sign of an escalation and, therefore, an indication of a risk of repetition that does justify arrest and the immediate separation of the aggressor. Hence the problem cannot be resolved with an inverse automatism —«there are community ties, therefore no arrest»—, but through the individualised assessment of risk (VioGén System). The rule, in short, is neither to always arrest nor to never arrest, but to check, case by case, whether to the indications is added a procedural danger that makes arrest a necessary measure.²⁵

6.5. Situations in which arrest is warranted

To state that a complaint is not enough does not mean, in any way, that arrest is improper in gender-based violence or in sexual assault. It will be warranted —and often mandatory— where the two axes already examined (4.2 and 4.3) converge: a sufficient underlying support (the fumus) and a specific precautionary purpose (the periculum), the judgment of necessity and proportionality having been passed. Corroboration of the complaint —visible injuries, a medical report, witnesses, traces— operates on the first axis: it consolidates the reasonable indications of criminality and of authorship, but it is the additional presence of a purpose that makes the arrest legitimate. It is, then, not corroboration on its own —as was warned in 6.4—, but its conjunction with a precautionary purpose, that authorises arrest.

Paradigmatic situations of that convergence are:

• (a) flagrante delicto or quasi-flagrante delicto, in which the officer perceives the offence or its immediate effects —the indications are obvious and, as a rule, the purpose of bringing the assault to an end and protecting the victim is present—;
• (b) a corroborated complaint accompanied by a present risk to the victim —assessed in accordance with the VioGén System— that makes her immediate separation from the aggressor necessary;
• (c) the presence of a risk of flight or of destruction of evidence alongside sufficient indications; and
• (d) notably, the breach of a restraining measure or penalty in force (art. 468 CP), which constitutes a fresh offence —usually flagrante delicto— and entails an objective increase in risk: here both the fumus (the breach itself) and the periculum (the heightened risk to the victim) are present at once.

In all of them, what justifies the arrest is not the nominal gravity of the act or the mere solidity of the evidence, but that to the indications is added a precautionary purpose that the summons cannot satisfy.

6.6. Situations in which arrest is not warranted

Correspondingly, arrest finds no cover where its substantive precondition or its necessity is lacking:

• (a) complaints devoid of any corroboration and without flagrante delicto, in which the account does not even reach the threshold of reasonable suspicion;
• (b) facts which, even though reported, do not bear the features of an offence or constitute a petty offence subject to the limit of art. 495;
• (c) the absence of appreciable risk and of any procedural danger, with a person reported who is identified and has community ties and whose appearance can be secured by summons (art. 796 LECrim).

In these cases, arresting protects no legitimate interest additional to that already served by the investigation, and becomes a disproportionate interference.

6.7. The risk of automatism

Practice is familiar with an understandable temptation: to turn every complaint of gender-based or sexual violence into an immediate arrest, out of caution, institutional pressure or fear of failing to act. That impulse towards automatism is, however, legally untenable. Neither does the law impose it —art. 492 requires indications, not complaints— nor does the Constitution tolerate it —arrest is exceptional and proportionate—. Automatism is, moreover, counterproductive: unfounded arrests translate into releases or dismissals that erode the credibility of the system and, where the case arises, generate liability. The correct response is not to always arrest, but to always assess: the risk, the indications and the necessity of the measure.

VII. Consequences of Arrest Without a Basis: Unlawful Detention

The importance of all the foregoing is seen in its punitive flip side. To arrest outside the cases and the manner laid down by law is not a mere irregularity: it may constitute an offence. Article 530 CP punishes the authority or official who, where criminal proceedings exist, orders, carries out or prolongs a deprivation of liberty in breach of the time limits or of the other constitutional or statutory safeguards. And Article 167 CP punishes, with the aggravated penalties for unlawful detention, the authority or official who, outside the permitted cases and without criminal proceedings being under way, deprives another of their liberty.²⁶

To this protection under the criminal law is added the procedural protection of habeas corpus (art. 17.4 CE and LO 6/1984), which allows the lawfulness of the arrest to be reviewed immediately, and the financial liability of the State for wrongful arrests. Together they confirm that the legal order takes the exceptional character of the deprivation of liberty seriously: it is not a disposable formality, but a measure that is supervised and, where appropriate, punished.

VIII. Conclusions

1. Police custody is an exceptional interference with the fundamental right to liberty (art. 17 CE), subject to a reservation of statute and to the principles of necessity and proportionality. It is permissible only in the cases and in the manner prescribed by law (art. 489 LECrim).
2. Its substantive preconditions are flagrante delicto (art. 490) or the existence of «reasonable grounds» to believe in an act bearing the features of an offence and in the participation of the suspect (art. 492.4.º). An objective basis is required, not a subjective conviction or a formal accusation.
3. Alongside the substantive precondition (the indications), arrest requires a constitutionally legitimate purpose, which art. 492 does not list and which is distilled from the regime of pre-trial detention (art. 503 LECrim) and from the constitutional case law: to secure submission to the proceedings (risk of flight), to preserve the evidence, to prevent repetition or to protect the victim. Excluded are the anticipation of punishment, social alarm and pressure on the person under investigation. Each purpose is appraised in the specific case, never by the gravity of the act alone.
4. Gender-based violence receives special treatment at the statutory level —the gender-violence statutes (LO 1/2004; LECrim) heighten the purpose of protecting the victim and articulate dedicated procedures—, but that treatment operates within the constitutional proportionality test, identical for every offence, to which such statutes are subordinate and which the Constitutional Court supervises. The VioGén instruments, of sub-statutory rank, cannot alter the test or add preconditions: they assess risk and inform the purpose of protection, but a risk level is not, in itself, a basis or cause for arrest.
5. The mere filing of a complaint for gender-based violence or for sexual assault is not, on its own, a sufficient precondition to arrest. A complaint is notitia criminis that gives rise to a duty to investigate; it does not satisfy, without assessment, the precondition of art. 492.4.º, nor does it dispense with the proportionality judgment.
6. A corroborated complaint (a medical report, a bruise, a minor injury) reinforces the fumus boni iuris —the appearance of an offence—, but it does not create the periculum or precautionary purpose, which is an autonomous and distinct requirement. If the indications are solid but there is no risk of flight, of repetition or to the evidence —which the documentation of the injury, moreover, already secures—, arrest is unnecessary and disproportionate: the proportionate response is to summons the person under investigation (art. 796 LECrim), not to deprive them of liberty.
7. The request —or the absence of a request— for a protection order is immaterial for the purposes of arrest. It is neither a sufficient precondition (the order is granted by the judge, art. 544 ter LECrim) nor a necessary one (the offences are public or, in the case of sexual assault, prosecutable, and protection operates independently of the complaint).
8. Arrest is warranted, by contrast, where to a sufficient underlying support (flagrante delicto or a corroborated complaint) is added a precautionary purpose —a present risk to the victim, a danger of flight or of destruction of evidence—, or in the face of the breach of a measure in force (art. 468 CP), which combines both axes. The decisive point is the convergence of indications and purpose, not corroboration on its own.
9. Arrest is not warranted in the face of complaints without corroboration and without flagrante delicto, atypical facts or petty offences (art. 495), or where there is no risk or procedural danger and appearance can be secured by summons (art. 796 LECrim).
10. The governing criterion is not «always arrest», but always assess: automatism has no statutory or constitutional cover and may lead to unlawful detention (arts. 167 and 530 CP), in addition to disciplinary and financial liability.
11. The effective protection of the victim and respect for the safeguards owed to the person under investigation are not opposing objectives: both are better served by an individualised, reasoned and proportionate police response, grounded in the assessment of risk (VioGén System) and in prompt judicial intervention.

Notes

1. The seventy-two-hour period is a maximum, not a term that may be exhausted routinely: the constitutional case law has insisted that the duration must be confined to what is «strictly necessary», so that the unjustified prolongation of an arrest —even within the 72 hours— may infringe art. 17 CE.
2. ECtHR, judgment in Fox, Campbell and Hartley v. United Kingdom, 30 August 1990. The requirement of an objective factual basis, and not of mere conjecture or subjective suspicion, is settled doctrine of the Strasbourg Court in the interpretation of art. 5.1.c ECHR.
3. The reference to «correctional imprisonment» is a vestige of the penalty system of the 1870 Code and must today be read in terms of the gravity of the penalty under the Criminal Code in force. For police action at the investigation stage, the truly operative situation is that of number 4.º of art. 492, concerning someone who has not yet been formally accused.
4. The wording in force of art. 520 LECrim derives from Organic Act 13/2015 and Act 5/2015, which transposed, among others, Directive 2013/48/EU on the right of access to a lawyer. Access to the essential elements of the proceedings is conceived, precisely, as an instrument enabling the deprivation of liberty to be challenged.
5. This is settled doctrine of the Constitutional Court regarding interferences with fundamental rights; for all, judgments STC 66/1995 and STC 207/1996, which articulate the threefold test of suitability, necessity and proportionality in the strict sense.
6. On the exceptional character of arrest and its restrictive interpretation, see STC 341/1993 of 18 November.
7. The purposes of pre-trial detention were distilled by the constitutional case law (notably, STC 128/1995 of 26 July; and STC 47/2000 of 17 February, which referred the internal question of unconstitutionality on arts. 503-504 LECrim) and enacted by Organic Act 13/2003 in art. 503: to secure the presence of the person under investigation, averting the risk of flight (art. 503.1.3.º a); to prevent the concealment, alteration or destruction of evidence (503.1.3.º b); and to protect the victim (503.1.3.º c); to which art. 503.2 adds the risk of repetition of the offence.
8. STC 47/2000: the generic social alarm that an offence may produce is content proper to general deterrence —a purpose of punishment—, unrelated to the precautionary aim; on its own it cannot ground the deprivation of liberty.
9. ECtHR, Letellier v. France, 26 June 1991: the danger of flight cannot be assessed by the gravity of the penalty alone, but by reference to the set of circumstances (the family, work and economic situation and the community ties of the person affected). To the same effect, the constitutional doctrine on the reasoning of pre-trial detention.
10. STC 59/2008 of 14 May, which dismissed the question of unconstitutionality on art. 153.1 CP after examining its proportionality and its compatibility with the principle of equality. It is an illustration that the gender-violence statutes operate under the supervision of the constitutional test, not above it.
11. Instructions and service orders (art. 6 of Act 40/2015) are instruments for the internal direction of administrative activity; their breach does not, in itself, affect the validity of the acts and they do not constitute a source of rights or obligations for citizens.
12. The VPR and the successive VPER are structured professional-judgment questionnaires that yield a risk level (low, medium, high or extreme). Their function is to order and standardise the assessment and to trigger police protection measures, not to decide the personal situation of the person under investigation, which is a matter for the judicial authority.
13. The practical risk is that the ease and the appearance of objectivity of the form may induce treating the risk level as a cause for arrest. As set out in 4.4, an administrative instruction cannot create that effect: arrest continues to require indications, a precautionary purpose and proportionality, appraised and reasoned in the specific case.
14. Organic Act 8/2021 of 4 June (LOPIVI), in force since 25 June 2021. Article 132.1 CP reserves, for a group of offences —among them those relating to the sexual freedom and indemnity of minors—, the computation of the limitation period from the moment the victim reaches thirty-five years of age.
15. Organic Act 4/2023 of 27 April. Following this reform, rape is punished in two modalities: art. 179.1 CP punishes carnal access by the vaginal, anal or oral route —or the introduction of body parts or objects by either of the first two routes— with imprisonment of four to twelve years; and art. 179.2 CP imposes imprisonment of six to twelve years where the assault is committed using violence or intimidation, or where the victim's will has been nullified by any cause. Article 180 lists the aggravating circumstances. Consent (art. 178.1 CP) remains the axis of the wrong.
16. As of June 2026 the bill has not yet been approved as an act. Since it places sexual deepfakes among the offences against moral integrity —and not, strictly, among the offences against sexual freedom—, its bearing on the object of this study is indirect; it is noted in order to complete the reform landscape.
17. Art. 191 CP. The pardon of the aggrieved party does not extinguish the criminal action in these offences. The requirement of a complaint or prosecution is a procedural prerequisite for prosecutability, which does not prevent arrest in flagrante delicto: the procedural condition affects the exercise of the action, not the power of immediate intervention in the face of an offence that is being committed.
18. The breach of a restraining penalty or precautionary measure (art. 468 CP) constitutes, in itself, an offence and, normally, a situation of flagrante delicto that authorises arrest; it is no longer the initial complaint, but a fresh and verifiable criminal act, that provides the support for the deprivation of liberty.
19. Instruction 1/2025 of the State Secretariat for Security, establishing a new protocol for the police assessment and management of the gender-violence risk level (VioGén-2 System), in force since 30 June 2025, replacing Instruction 4/2019.
20. The «Protocol Zero» shows that the protection of the victim is articulated through police and risk-monitoring instruments —not necessarily through the arrest of the person reported— and that it operates regardless of whether or not there is a complaint and of whether or not a protection order has been requested.
21. See, to this effect, the guidance of the Public Prosecutor's Office on precautionary measures in gender-based violence in the duty service, which stresses that the arrest of the alleged aggressor will be warranted where the nature of the facts or the situation of risk so advise, and that an automatic arrest, lacking that judgment, suffers from a defect at its origin.
22. This is the structure common to every precautionary measure, taken from civil procedure (art. 728 LEC) and carried over into criminal procedure: appearance of good right and danger arising from procedural delay (danger of flight and of obstruction). In pre-trial detention the periculum is enacted in the purposes of art. 503 LECrim; in arrest, whose regulation does not list them, its requirement is inferred by constitutional means.
23. Art. 796.1 LECrim, on the action of the judicial police in urgent proceedings (the expedited trial). In violence against women, the summons of the person reported is carried out before the Court for Violence against Women on the nearest working day and in coordination with it. The express provision for the summons «where no arrest has been made» shows that arrest is neither the mandatory response nor the only one.
24. Scholarship has described the statutory regulation of arrest as deficient, precisely because it does not specify its purposes. The constitutional case law supplies that silence by requiring that every personal precautionary measure be adopted on a judgment of reasonableness as to the purpose pursued and the surrounding circumstances, which rules out arrest devoid of any precautionary purpose.
25. The assessment is not discretionary: it must be reasoned in the police report and is subject to immediate judicial review (the bringing before a judge and, where appropriate, the hearing of art. 544 ter) and to habeas corpus. The existence of a risk, even a moderate one, may suffice as a precautionary purpose; its demonstrated absence, by contrast, deprives the arrest of support.
26. The distinction between arts. 530 and 167 CP turns, essentially, on whether or not the deprivation of liberty takes place within the framework of criminal proceedings and with what degree of departure from legality. To this is added the possible disciplinary liability and the financial liability of the Administration for abnormal functioning.

Sources

Legislation

• Spanish Constitution of 1978, arts. 17, 9.3, 53.1, 81.1 and 24 (liberty, hierarchy of norms, reservation of statute and judicial protection).
• Criminal Procedure Act (Royal Decree of 14 September 1882), arts. 259 to 269, 489 to 501, 520, 544 bis, 544 ter and 796 (summons of the person reported in the expedited trial).
• Criminal Code (Organic Act 10/1995), arts. 153, 167, 173, 178 et seq., 191, 468 and 530.
• Organic Act 13/2003 of 24 October, reforming pre-trial detention (arts. 503 and 504 LECrim).
• Organic Act 1/2004 of 28 December, on Comprehensive Protection Measures against Gender Violence.
• Organic Act 8/2021 of 4 June, on the comprehensive protection of children and adolescents against violence (LOPIVI); art. 132 CP (limitation).
• Organic Act 10/2022 of 6 September, on the comprehensive guarantee of sexual freedom, and Organic Act 4/2023 of 27 April.
• Bill for an Organic Act on the protection of minors in digital environments (in the legislative pipeline as of June 2026; amendment of the Criminal Code on sexual deepfakes and grooming).
• Act 27/2003 of 31 July, regulating the Protection Order for victims of domestic violence.
• Act 4/2015 of 27 April, on the Statute of the Victim of Crime.
• Organic Act 6/1984 of 24 May, regulating the habeas corpus procedure.
• Organic Act 13/2015 and Act 5/2015 (reform of art. 520 LECrim; Directive 2013/48/EU).
• Act 40/2015 of 1 October, on the Legal Regime of the Public Sector, art. 6 (instructions and service orders).
• European Convention on Human Rights, art. 5; International Covenant on Civil and Political Rights, art. 9.

Case law

• STC 341/1993 of 18 November (regime of arrest; restrictive interpretation).
• STC 128/1995 of 26 July (personal precautionary measures; fumus boni iuris and a constitutionally legitimate purpose).
• STC 47/2000 of 17 February (purposes of pre-trial detention; exclusion of social alarm; question of unconstitutionality on arts. 503-504 LECrim).
• STC 59/2008 of 14 May (constitutionality and proportionality of the differentiated criminal treatment in gender-based violence, art. 153.1 CP).
• STC 66/1995 and STC 207/1996 (proportionality test: suitability, necessity and proportionality in the strict sense).
• ECtHR, Fox, Campbell and Hartley v. United Kingdom, 30 August 1990 (requirement of reasonable suspicion, art. 5.1.c ECHR).
• ECtHR, Letellier v. France, 26 June 1991 (risk of flight; insufficiency of the gravity of the penalty as the sole criterion).

Documents and protocols

• Protocol of action of the Security Forces and Corps and of coordination with the judicial bodies for the protection of victims of domestic and gender violence.
• Comprehensive Monitoring System in cases of Gender Violence (VioGén / VioGén-2 System), Ministry of the Interior.
• Instruction 1/2025 of the State Secretariat for Security (VPR/VPER protocol; in force since 30 June 2025; repeals Instruction 4/2019).
• «Protocol Zero» for situations of victims in a position of possible lack of protection without a complaint.
• Office of the State Prosecutor General: guidance and papers on precautionary measures in gender-based violence in the duty service.

Methodological note: this document has a doctrinal and informative purpose and does not constitute legal advice for a specific case. The normative references are updated as of June 2026; it is advisable to check for subsequent reforms and the case law applicable to the particular situation.