and 7(2) of the Convention, in relation to Article 1(1) of this instrument. Also, the fact that the detention was not based on objective criteria, but rather on the application by the police officers of stereotypes relating to Mr. Tumbeiro’s appearance and its presumed lack of correlation to his surrounding signified that the police intervention was a discriminatory and, consequently, arbitrary action that violated Articles 7(3) and 24 of the American Convention, in relation to Article 1(1) of this instrument. B.1.3. Inadequacy of the law and existence of a practice that violated the Convention in both cases 88. The Court recalls that, in its Merits Report, the Inter-American Commission observed that the regulation that granted the authority applied in this case was “extremely vague and d[id] not include specific references to objective reasons or parameters that could potentially justify suspicion. In addition, the legislation d[id] not include any requirement that the police authorities be accountable, in writing and to their superiors, with details of the reasons that led to the arrest and search. In addition, from the context described in the section on proven facts, it appear[ed] that the incidents in this case [were] not isolated, but rather that this regulation and its application in practice ha[d] resulted in abusive actions by the police.”118 The State accepted this conclusion in its act of acknowledgement of responsibility. 89. In this regard, the Court recalls that Article 7(2) of the Convention requires not only the existence of regulations that establish the “causes” and “conditions” that authorize the deprivation of physical liberty, but also that these be sufficiently clear and detailed, so that they respect the principle of legality and prior legal definition of offenses as this has been understood by this Court in its case law. In this regard, the Court has indicated that “the categorization of an act as unlawful and the establishment of its legal effects must pre-exist the conduct of the individual who is considered to be an offender because, to the contrary, people would not be able to conduct themselves in keeping with a valid known legal system that expresses social rebuke and its consequences.”119 90. The Court considers that regulations that determine the powers of police officials in relation to crime prevention and investigation must include specific and clear indications of parameters that avoid interceptions of a car or detentions for identification purposes being carried out arbitrarily. Consequently, those provisions that include and enable conditions that permits a detention without a court order or in flagrante delicto, in addition to meeting the requirements of legitimate purpose, appropriateness and proportionality, must establish the existence of objective elements so that it is not mere police intuition or subjective criteria, that cannot be verified, that are the reasons for a detention. This means that the purpose of the legislation enabling this type of detention must be for the authorities to exercise their powers when faced with the existence of real, sufficient and concrete acts or information that, concurrently, would permit an objective observer to reasonably infer that the person detained was probably the perpetrator of a criminal offense or misdemeanor. This type of regulation should also observe the principle of equality and non-discrimination in order to avoid hostility towards certain social groups based on categories prohibited by the American Convention. 91. On this point, the Court notes the opinion of expert witness Juan Pablo Gomara that, faced with the need to establish a standard of proof as a presumption for police action during 118 Merits report (merits file, folio 22). Case of Norín Catrimán et al. (Leaders, members and activist of the Mapuche Indigenous People) v. Chile, supra, para. 106, and Case of Pollo Rivera et al. v. Peru. Merits, reparations and costs. Judgment of October 21, 2016. Series C No. 319, para. 219. 119 29