23 102. The Inter-American Court has also written that the duty to investigate is one of means, 118 not of results. It has also held that in order to comply with the obligation to investigate and punish, the State must remove all the de facto and de jure obstacles and mechanisms that maintain impunity, grant sufficient guarantees of security to witnesses, judicial authorities, prosecutors, other judicial agents, and 119 the next of kin of the victims, and use all possible measures to advance the proceeding. 103. The IACHR has written that “in order to establish in a convincing and credible manner that [a] result was not the product of a mechanical implementation of certain procedural formalities without the State genuinely seeking the truth, the State must show that it carried out an immediate, exhaustive and 120 impartial investigation” and must explore all the investigative leads possible that might identify the authors of the crime, so that they can be prosecuted and punished. The Court has established that the obligation to investigate a death means that the effort to determine the truth with all diligence must be 121 evident as of the very first procedures. The State may be liable for a failure to order, practice or 122 evaluate evidence that may have been essential for a proper clarification of the facts. 104. The Inter-American Court has defined the guiding principles to be observed in an investigation into a violent death. The State authorities who conduct an investigation of this type must try, at the very least, inter alia: (i) to identify the victim; (ii) to recover and preserve the probative material related to the death in order to assist in any potential criminal investigation of those responsible; (iii) to identify possible witnesses and obtain their statements in relation to the death under investigation; (iv) to determine the cause, manner, place and time of death, as well as any pattern or practice that could have caused the death, and (v) to distinguish between natural death, accidental death, suicide and homicide. 123 In addition, the scene of the crime must be searched exhaustively, and autopsies and tests of the human remains must be performed rigorously by competent professionals using the most appropriate 124 125 procedures. In the case of homicides, specific evidence must be preserved if rape is suspected. 105. The Inter-American Court has also written that the international standards indicate that, regarding the crime scene, the investigators must, at the very least: photograph the scene and any other physical evidence, and the body as it was found and after it has been moved; gather and conserve the samples of blood, hair, fibers, threads and other clues; examine the area to look for footprints or any other trace that could be used as evidence, and prepare a detailed report with any observations regarding the 118 I/A Court H.R., Case of Baldeón García. Judgment of April 6, 2006. Series C No. 147, paragraph 93. 119 I/A Court H.R., Case Carpio Nicolle et al. Judgment of November 22, 2004. Series C No. 117, paragraph 134 120 IACHR, Merits Report No. 55/97, Juan Carlos Abella et al. (Argentina), November 18, 1997, paragraph 412. 121 I/A Court H.R., Case of González et al. (“Cotton Field”) v. Mexico. Preliminary Objection, Merits, Reparations and Costs. Judgment of November 16, 2009. Series C No. 205, paragraph 300; I/A Court H.R. Case of the Miguel Castro Castro Prison. Judgment of November 25, 2006. Series C No. 160, paragraph 383. 122 I/A Court H.R., Case of the “Street Children” (Villagrán Morales et al.). Judgment of November 19,1999. Series C No. 63, paragraph 230. 123 I/A Court H.R., Case of González et al. (“Cotton Field”) v. Mexico. Preliminary Objection, Merits, Reparations and Costs. Judgment of November 16, 2009. Series C No. 205, paragraph 300; IACHR, Report No. 10/95, Manuel Stalin Bolaños (Ecuador), September 12, 1995, paragraphs 32 - 34; Report No. 55/97, Juan Carlos Abella et al. (Argentina), November 18,1997, paragraphs 413 to 424; Report No. 48/97, Ejido Morelia (Mexico), April 13, 1996. paragraphs 109 - 112. IACHR, Access to Justice for Women Victims of Violence in the Americas, OEA/Ser. L/V/II. doc.68, January 20, 2007, paragraph 47. 124 I/A Court H.R., Case of González et al. (“Cotton Field”) v. Mexico. Preliminary Objection, Merits, Reparations and Costs. Judgment of November 16, 2009. Series C No. 205, paragraph 300; I/A Court H.R. Case of Juan Humberto Sánchez v. Honduras. Preliminary Objection, Merits, Reparations and Costs. Judgment of June 7, 2003. Series C No. 99, paragraph 127; I/A Court H.R. Case of Escué Zapata v. Colombia. Merits, Reparations and Costs. Judgment of July 4, 2007. Series C No. 165, paragraph 106; I/A Court H.R., Case of Kawas Fernández v. Honduras. Merits, Reparations and Costs. Judgment of April 3, 2009 Series C No. 196, paragraph 102. 125 The victim’s oral, vaginal and rectal fluids must be preserved, as must foreign and pubic hairs. United Nations, Manual on the Effective Prevention and Investigation of Extra-Legal, Arbitrary and Summary Executions, U.N. Doc. E/ST/CSDHA/.12 (1991), paragraphs 29-30.