b. Due diligence in the gathering of evidence 153. The IACHR reiterates that the violations perpetrated in this case should have been investigated with the strictest adherence to due diligence, given the seriousness of the crime and the nature of the rights violated—the rights to life and freedom of expression—which sent out a clearly intimidating message to those who practice journalism in the area. 154. This includes the obligation to diligently implement measures for obtaining and preserving evidence. According to the United Nations Principles on the effective prevention and investigation of ExtraLegal, Arbitrary and Summary Executions (“United Nations Principles”), as well as the Model Protocol for a legal investigation of Extra-legal, Arbitrary and Summary Executions (“Minnesota Protocol”), the state authorities that carry out an investigation of this type must, at a minimum, attempt to, inter alia: (a) identify the victim; (b) recover and preserve evidence pertaining to the death for purposes of assisting in any potential criminal investigation of the perpetrators; (c) identify potential witness and obtain their statements regarding the death under investigation; (d) determine the cause, manner, place, and time of death, as well as any pattern or practice that might have caused the death, and (e) distinguish among natural death, accidental death, suicide, and homicide. Additionally, it is necessary for the crime scene to be thoroughly investigated, and for autopsies and analyses of human remains to be rigorously performed, by competent professionals and through the most appropriate procedures.150 155. In the case of violence against journalists, criminal investigations must also exhaust the lines of investigation related to the practice of journalism. The Inter-American Court has held that, in complying with its obligations of investigation and protection, the State must take account of the reasonable connection between the attack motivated by the exercise of freedom of expression and the subsequent acts of violence perpetrated.151 156. Under these principles, the State is also required to investigate, and if appropriate, punish all perpetrators of crimes, including direct perpetrators, masterminds, accomplices, collaborators, and accessories to human rights violations. Moreover, it must investigate the structures through which the crimes are committed and the criminal organizations to which the perpetrators belong. As previously explained, “due diligence” demands that the investigations conducted by the State take account of “the complexity of the facts, the context in which they occurred, and the systematic patterns that explain why the events occurred,” ensuring that there are no “omissions in gathering evidence or in the development of logical lines of investigation.”152 This obligation is especially relevant in cases of violence against journalists, which oftentimes are committed by criminal networks that act with the tolerance or acquiescence of State agents, and in which the direct perpetrator of the crime is merely carrying out orders. 157. With regard to the collection and preservation of evidence, Inter-American Commission reiterates that in cases in which the unlawful, arbitrary, or summary of an individual is suspected, the collection and analysis of the physical evidence and the taking of statements from potential witnesses is essential in order to guarantee an effective investigation, according to the above-mentioned United Nations and Minnesota Model Protocol. 150 United Nations Principles on the effective prevention and investigation of Extra-Legal, Arbitrary and Summary Executions, Resolution 1989/65 Economic and Social Council, May 24, 1989; Model Protocol for a legal investigation of Extra-legal, Arbitrary and Summary Executions, UN Doc. E/ST/CSDHA/.12 (1991), Part III. See also, CIDH. Report nº 92/05. Case 12.418. Merits. Michael Gayle. Jamaica. October 24, 2005, para. 88-86; Report No. 10/95, Case No. 10.580, Manuel Stalin Bolaños Quiñones, Ecuador, September 12, 1995, para. 32-34. 151 I/A Court H.R., Case of Vélez Restrepo and Family v. Colombia. Preliminary Objection, Merits, Reparations, and Costs. Judgment of September 3, 2012. Series C No. 248. Para. 211. 152 I/A Court H.R., Case of the Rochela Massacre v. Colombia. Merits, Reparations and Costs. Judgment of May 11, 2007. Series C No. 163. Para. 158; I/A Court H.R., Case of Manuel Cepeda Vargas v. Colombia. Preliminary Objections, Merits, Reparations and Costs. Judgment of May 26, 2010. Series C No. 213. Para. 106-110 & 167.