50 164. The Court notes that the judicial authorities did not develop an investigation into the combination of probative elements that pointed to security forces, including senior military leaders. As a result, the investigations have been partially ineffective. In addition, there was a lack of diligence with regard to the development of a line of investigation, which took into account the complex structure of the perpetration of the crime (supra para. 158). This failure has caused some of the investigations into the Rochela Massacre to be ineffective, particularly with regard to the investigation into the responsibility of senior military commanders in the area. In this regard, the absence of an exhaustive investigation into the operational structure of the paramilitary groups and their linkages and relationships with State agents, including members of the security forces, has been one of the factors that has hindered the investigation, prosecution and punishment of all those responsible. In particular, this affected the determination of possible responsibility of the commanders of the military battalions located within the area of operations of the paramilitary groups tied to the massacre. This situation inevitably encouraged impunity for the grave human rights violations committed by the paramilitary groups with the support and collaboration of State agents. * * * Threats against judges, witnesses and next of kin 165. From the body of evidence, the Court has determined that, during the investigations into the events of this case, there were threats against judges, witnesses and next of kin. These threats have influenced the effectiveness of the proceedings. As has been indicated (supra para. 158), due diligence in the investigations implies taking into account the patterns of operation of the complex structure of individuals who executed the massacre because this structure remained in place after the massacre had been committed, and because, precisely to ensure its impunity, it operates by using threats to instill fear in investigators and in possible witnesses, or in those who have an interest in seeking the truth, as in the case of the victims’ next of kin. The State should have adopted protective and investigative measures in order to confront this type of intimidation and threats. 166. Indeed, a few months after the investigation started, the proceedings were transferred from the judicial district, given “[c]ircumstances of public order in the Magdalena Medio area,” and the “threats against witnesses, and the need to protect them.”157 In addition, the Fifth and Sixth Judges of Bucaramanga and the Sixth Public Order Judge of Bogotá [Jueces Quinto y Sexto de Bucaramanga y Sexto de Orden Público de Bogotá] based their request to change the court’s venue on the fact that they had received “death threats.” Moreover, in the session of the National Criminal Investigation Council [Consejo Nacional de Instrucción Criminal] of March 16, 1989, it was proposed that “to protect the life of the witnesses, they should leave the country.”158 167. The Commission and the representatives also alleged that “three witnesses” and “one investigating agent” were murdered, to which the State responded that “there is no evidence connecting [these deaths] to the investigations.” 157 Cf. report of August 25, 2006, issued by the National Human Rights and International Humanitarian Law Unit (record of evidences to the State’s reply brief, volume I, evidence 1, page 4574). 158 Cf. resolution 1945 of June 29, 1989, issued by the Minister of Justice (record of evidences to the State’s reply brief, volume I, evidence 3D, page 4634).