35 March 22, 2002, a group of soldiers made reconnaissance near Barranca Tecoani, returning to their base at approximately four in the afternoon,94 in other words, one hour after the incident. 110. For its part, in its Recommendation 046/2003 concerning this case, the National Human Rights Commission did not address responsibility regarding the rape, but rather took as affirmed that from the attestations in the case file “one fact [among others] is clear: that personnel of the Méndez Operations Base of the 41st Infantry Battalion of the Mexican Army were present at the time and in the place.”95 iii) Expert evidence and loss of evidence in State custody 111. In addition to the statements of the alleged victim, the official expert studies for the presence of sperm and acid phosphates studies concluded “the presence of seminal liquid on the two swabs obtained and […] identified sperm cells.”96 112. However, even though seminal liquid and sperm cells had been found, the samples were inexplicably used up or thrown away by the expert officials, preventing other tests from being carried out; some of them of fundamental importance, for example, DNA. This fact, acknowledged by the State (supra paras. 16 and 18), which the Court considers extremely serious, has obstructed the judicial determination and clarification of the facts to date. In this regard, the Court has indicated that, in principle, the burden of proof regarding the facts on which the complaint is based corresponds to the petitioner. Nevertheless, it has underscored that, contrary to domestic criminal law, in proceedings on human rights violations, the State’s defense cannot be based on the impossibility of the petitioner to provide evidence, when it is the State that controls the means to ascertain facts that occurred on its territory.97 In this case, the failure to clarify the facts responds, above all, to the destruction of this fundamentally important evidence, while in the custody of the State. iv) Other persuasive elements 113. On the other hand, the Court also finds that the credibility of Mrs. Fernández Ortega’s story appears to be supported by other persuasive elements. In its Recommendation 048/2003, the National Human Rights Commission referred to the existence of a psychiatric certification issued by a medical expert adjoined to that State agency, “which indicates that the victim was exposed to a traumatic event.”98 Moreover, a 2009 psychological report of Mrs. Fernandez Ortega concluded that “the facts narrated […] concerning the rape are coherent with the psychological symptoms suffered, because such symptoms are emotional reactions typical of a petition, tome III, folios 1628, 1634, 1642, 1648, 1654, 1659, 1665, 1671, 1677, 1693, 1700, 1717, 1750, and 1762). 94 Cf. Statements of ten infantry soldiers, four corporals of the infantry and one subliutenent of the infantry before the Military Public Prosecutor on April 1, 2002 (case file of annexes to the petition, tome III, folios 1635, 1641, 1648, 1654, 1660, 1665, 1671, 1676, 1693, 1699, 1710, 1727, 1744, 1756, and 1762). 95 Cf. Recommendation No. 048/2003 issued by the National Human Rights Commission, supra note 87, folio 578). 96 Cf. Forensic Chemsitry Report No. PGJE/DSGP/XXVI-II/305/02, supra note 84, folio 7830. 97 Cf. Case of Velásquez Rodríguez. Merits, supra note 27, para. 135; Case of Escher et. al. v. Brazil. Preliminary Objections, Merits, Reparations, and Costs. Judgment of July 6, 2009. Series C No. 200, para. 127, and Case of Radilla Pacheco, supra note 33, para. 89. 98 Cf. Recommendation No. 048/2003 issued by the National Human Rights Commission, supra note 87, folio 578.