and effective investigation.398 However, in cases such as this one, where there are no indications of violence in the death of the presumed victim (and nor was this alleged) since her death occurred in a hospital and it is reasonably probable that it was due to natural or accidental causes, a non-judicial investigation, such as the one conducted by the authorities where Manuela had been detained may be sufficient.399 Manuela’s death certificate records that the “disease or pathological condition that was the direct cause of death” was nodular sclerosis Hodgkin’s lymphoma.400 Therefore, the Court considers that it has not been proved that the State is responsible for the alleged failure to ensure access to justice, pursuant to the rights to judicial guarantees and to judicial protection recognized in Articles 8(1) and 25 of the American Convention, to the detriment of Manuela’s family. B.6 The impact of the discrimination that occurred in this case 248. The Court recalls that, as a crosscutting condition for the accessibility of health services, the State is obliged to ensure that everyone is treated equally.401 Thus, pursuant to Article 1(1) of the American Convention, discriminatory treatment is not permitted based on a person’s sex. In the current stage of the evolution of international law, the fundamental principle of equality and non-discrimination has entered the realm of jus cogens and permeates the whole legal system.402 249. The Court has also indicated that the right to equality guaranteed by Article 24 of the Convention has two dimensions (supra para. 156). The second dimension is material or substantive and requires the adoption of positive measures of promotion in favor of groups that have historically been marginalized or discriminated against owing to the factors mentioned in Article 1(1) of the American Convention. This means that the right to equality entails the obligation to adopt measures to ensure that the equality is real and effective; in other words, to correct existing inequalities, promote the inclusion and participation of historically marginalized groups, ensure to disadvantaged persons or groups the effective enjoyment of their rights and, in sum, provide everyone with the real possibility of enjoying the realization of material equality in their own cases. To this end, States must actively address situations of exclusion and marginalization.403 250. The duty to ensure material equality concurs with Articles 3 and 4 of the Convention on the Elimination of All Forms of Discrimination against Women, which establish: Article 3 States Parties shall take in all fields, in particular in the political, social, economic and cultural fields, all appropriate measures, including legislation, to ensure the full development Cf. Case of Vera Vera et al. v. Ecuador, supra, para. 87, and Case of the Landaeta Mejías Brothers et al. v. Venezuela. Preliminary objections, merits, reparations and costs. Judgment of August 27, 2014. Series C No. 281, para. 253. 398 399 Cf. International Committee of the Red Cross, Guidelines for Investigating Deaths in Custody, October 2013, Article 1(2)(c). Available at: https://www.icrc.org/en/doc/assets/files/publications/icrc-002-4126.pdf 400 Manuela’s death certificate dated April 30, 2010 (evidence file, folios 3780 and 3783). Cf. Case of Poblete Vilches et al. v. Chile, supra, para. 122, and Case of Guachalá Chimbo et al. v. Ecuador, supra, para. 166. 401 Cf. Juridical Status and Rights of Undocumented Migrants. Advisory Opinion OC-18/03 of September 17, 2003. Series A No. 18, para. 103, and Case of the Workers of the Fireworks Factory of Santo Antônio de Jesus and their families v. Brazil, supra, para. 182. 402 Cf. Case of the Workers of the Fireworks Factory of Santo Antônio de Jesus and their families v. Brazil, supra, para. 199, and Case of Guachalá Chimbo et al. v. Ecuador. Merits, reparations and costs, supra, para. 167. 403 70