40 the Convention, and be conducive to the effective observation of the guarantees established thereto. 90. Likewise, the Convention prohibits the arrest or imprisonment by methods that although qualified as legal, may in the practice result unreasonable or out of The Court has established that in order to comply with the proportion.57 requirements necessary to restrict the right to personal liberty, there must be sufficient evidence to lead to a reasonable supposition of guilt of the person submitted to a proceeding and the arrest must be strictly necessary to ensure that the accused party will not impede an effective development of the investigations nor will he evade the action of justice. When ordering restrictive measures to freedom it is precise that the State justify and prove the existence, in the specific case, of those requirements demanded by the Convention.58 91. In this case the arrest of the victims was part of a collective and programmed arrest, in which approximately 128 people were detained, without an arrest warrant and without having been caught in the act of committing a crime, and that was carried out with the declared purpose of avoiding disturbances during the parades that would take place to celebrate the National Independence Day (supra para. 79(5)). 92. The Tribunal understands that a collective arrest may represent a mechanism to guarantee public security when the State has elements to prove that the actions of each of the persons affected fits into one of the causes of arrest established in its internal norms consistent with the Convention. That is, when there are elements to individualize and separate the behaviors of each of the detainees and that there is, at the same time, control of the judicial authority. 93. Therefore, a massive and programmed arrest of people without legal grounds, in which the State massively arrests people that the authority considers may represent a risk or danger to the security of others, without substantiated evidence of the commission of a crime, constitutes an illegal and arbitrary arrest. Consistent with the aforementioned, in the Case of Bulacio the Court established that the razzias are not compatible with the respect for fundamental rights, among others, the presumption of innocence, the existence of a legal arrest warrant –except in the case of a crime detected in the act- and the obligation to inform the legal guardians of all minors.59 94. This Tribunal considers that the fundamental principle of equality and nondiscrimination belongs to the realm of jus cogens that, of a peremptory character, entails obligations erga omnes of protection that bind all States and result in effects with regard to third parties, including individuals.60 57 Cfr. Case of López Álvarez, supra note 55, para. 66; Case of García Asto and Ramírez Rojas, supra note 55, para. 105; and Case of Palamara Iribarne, supra note 10, para. 215. 58 Cfr. Case of López Álvarez, supra note 55, para. 69; Case of Palamara Iribarne, supra note 10, para. 198; and Case of Acosta Calderón, supra note 13, para. 111. 59 60 Cfr. Case of Bulacio, supra note 54, para. 137. Cfr. Juridical Condition and Rights of the Undocumented Migrants. Advisory Opinion OC-18/03 of September 17, 2003. Series A No. 18, para. 110.