- 37 - threats were reported, precisely as a measure of prevention to forestall them and, in this way, help prevent Senator Cepeda’s execution or at least try to prevent it. There is no evidence that the State conducted an investigation of this kind at the appropriate time. Indeed, in view of the context of violence faced by the UP and the PCC in Colombia at the time of the facts, the obligation of due diligence in the face of the reports of death threats acquired a special more rigorous nature, because it required the State to prevent the violation of the rights of Senator Cepeda Vargas.135 Since this obligation of means is more rigorous, it demanded prompt and immediate action by the police, prosecutorial and judicial authorities ordering the opportune and necessary measures to determine the authors of the threats made and the crimes committed in this context.136 102. Consequently, in the said context, the execution of Senator Cepeda Vargas was fostered, or at least permitted, by the series of abstentions of several public authorities and institutions from adopting the necessary measures to protect his life, in particular the absence of an adequate investigation into the threats within the framework of an alleged plan to exterminate leaders of the UP. In this case, it is obvious that the execution of a senator of the Republic could not have been perpetrated without the necessary planning (supra para. 101) and coordination (infra paras. 114 and 115). The failure to comply with the obligation to respect and guarantee Senator Cepeda’s right to life commenced as of that moment, given the serious shortcomings in the State’s obligations of prevention and of protection. B. THE OBLIGATION VARGAS TO RESPECT THE RIGHT TO LIFE OF SENATOR CEPEDA 103. To determine the scope of the State’s responsibility for the act perpetrated against Senator Cepeda Vargas by various agents, various contributions to the domestic investigations and proceedings must be examined, because the two sergeants of the Colombian Army sentenced and convicted as the perpetrators could not have acted alone in the execution. The State acknowledged this when admitting that the delay in the investigations thwarted the determination of the masterminds (supra paras. 13). As the authorities themselves have confirmed, the execution was perpetrated by several individuals; 137 hence, a division of tasks can be observed.138 Thus, while one group of individuals shot Senator Cepeda, other groups protected that group and ensured its escape.139 However, the failure to identify all the participants in the facts in the course of criminal proceedings does not prevent the Court from 135 Cf. Case of Velásquez Rodríguez v. Honduras. Merits, supra note 36, paras. 174 and 175. 136 Cf. Pueblo Bello Massacre v. Colombia. Merits, reparations and costs. Judgment of January 31, 2006. Series C No. 140, para. 126. See also, mutatis mutandi, Case of González et al. (“Campo Algodonero”) v. Mexico, supra note 15, para. 283; Case of the “Mapiripán Massacre” v. Colombia. Merits, reparations and costs, supra note 22, para. 123, and Case of Valle Jaramillo et al. v. Colombia, supra note 16, para. 76. 137 The judge of first instance indicated that Senator Cepeda Vargas “was killed by several individuals who intercepted his vehicle, and it was ascertained that some of them were driving in a white Renault 9 Brio.” Judgment delivered by the Third Criminal Court of the Santafé de Bogotá Specialized Circuit in Investigation No. 5393-3, on December 16, 1999, supra note 75, folio 1657. 138 Similarly, the Evaluation Report by the office of the Second District Attorney of Santafé de Bogotá in case No. 143-6444 of 1997, supra note 96, folio 1418. 139 Cf. Evaluation Report by the office of the Second District Attorney of Santafé de Bogotá in case No. 1436444 of 1997, supra note 96, folio 1418.