62 prisons, the presumption must be that the State is responsible for what happens to persons in its 199 custody. 299. The Commission observes that it has been duly established that Lucas Matías Mendoza had hematomas on the soles of his feet, and that Claudio David Núñez also had abrasions and the like on various parts of the body, as confirmed in medical reports prepared by physicians in the employ of the State. Two of these medical reports were prepared by doctors on the staff of the Medical Aid Service at Federal Penitentiary Complex No. 1. 300. The versions of events given by Claudio David Núñez and Lucas Matías Mendoza are consistent with each other and with the medical reports. Based on the information available, the Commission deems that there were serious indicia that the injuries both young men sustained, particularly those of Lucas Matías Mendoza, were not the result of a fight among inmates. His injuries were consistent with a form of torture described in the Istanbul Protocol as follows: “Falanga is the most common term for repeated application of blunt trauma to the feet (or more rarely to the hands or hips), usually applied with a 200 truncheon, a length of pipe or similar weapon.” The injuries that Lucas Matías Mendoza sustained are all the more serious because he was suffering from progressive blindness and by that time had lost almost all vision, which made him particularly vulnerable. 301. These findings are compounded by the conclusions listed below regarding the State’s failure to duly investigate the victims’ claims, especially in light of the results of the medical examinations they underwent. This means that the State failed to provide a satisfactory explanation of what happened to the victims and thus failed to disprove the presumption regarding its responsibility for what happens to persons in its custody. 302. In view of the foregoing, the Commission concludes that as a result of the use of methods demeaning to human dignity and calculated to inflict physical pain and suffering, Claudio David Núñez and Lucas Matías Mendoza were subjected to torture by agents of the State; as a consequence, the Argentine State violated their right to humane treatment recognized in Article 5 of the American Convention, and failed to comply with its obligation to prevent torture, an obligation undertaken in articles 1 and 6 of the Inter-American Convention to Prevent and Punish Torture. 4. Analysis of the investigations conducted. 303. As it has in previous cases, the Commission observes that the State has an international obligation to investigate, clarify and redress any violation of human rights denounced and to punish those 201 responsible, all in accordance with articles 1(1), 8 and 25 of the American Convention. In this particular case, the State had an obligation to identify those responsible for the violations of the right to humane treatment denounced by the petitioners. Furthermore, and by virtue of the principle of jura novit curia, the Commission believes that articles 1, 6 and 8 of the Inter-American Convention to Prevent and Punish Torture, transcribed above, are also relevant in the present case. 304. As for the duty to investigate any situation in which an act of torture may have been committed, the Inter-American Court has held that: in the light of the general obligation of the State Parties to respect and guarantee the rights of all persons subject to its jurisdiction, contained in Article 1(1) of the American Convention, the State has the obligation to commence immediately an effective investigation that may allow the 199 I/A Court H.R., Case of the Urso Branco Prison. Provisional Measures. Order of the Inter-American Court of Human Rights of June 18, 2002. Consideranda 8. I/A Court H.R., Case of Neira Alegría et al. v. Peru. Judgment of January 19, 1995. Series C No. 20, para. 65. 200 Istanbul Protocol. Manual on Effective Investigation and Documentation of Torture and Other Cruel, Inhuman or Degrading Treatment or Punishment. Office of the United Nations High Commissioner for Human Rights. Professional Training Series No. 8,t paragraph 203. 201 IACHR, Report No. 55/97, Case 11.137, Merits, Juan Carlos Abella, Argentina, November 18, 1997, para. 392.