- 46 - violations promoted and tolerated by a series of uncoordinated investigations that have been insufficient to duly clarify the facts and, consequently, have not complied satisfactorily with the obligation to investigate the violation of the right to life effectively. 126. Based on the above, together with the failure to comply with the obligations of prevention, protection and investigation with regard to the extrajudicial execution perpetrated, the Court declares the aggravated responsibility of the State for the violation of the rights to life and personal integrity established in Articles 4(1) and 5(1) of the Convention, in relation to Article 1(1) thereof, to the detriment of Senator Manuel Cepeda Vargas. IV.4 THE RIGHTS TO JUDICIAL GUARANTEES AND JUDICIAL PROTECTION (ARTICLES 8(1) AND 25 IN RELATION TO ARTICLE 1(1) OF THE AMERICAN CONVENTION) 127. First, it should be recalled that the State has partially acknowledged its responsibility for the violation of Articles 8, 25 and 1(1) of the Convention “essentially, because it had exceeded a reasonable time for the investigation” (supra para. 13). Later it indicated that, as a result of the delay in the investigations, “as yet, it had not been possible to establish the identity of the masterminds of the murder, and the underlying criminal structure that promoted it”;181 hence, an investigation opened ex officio was underway to identify other authors of the facts, and was at the pre-trial investigation stage. 128. In the instant case, the Court notes that, even though 16 years have elapsed since the facts occurred, the criminal proceedings are still open, without all those responsible having been prosecuted and eventually punished. This has exceeded excessively the time frame that could be considered reasonable for this purpose. In light of these considerations and of the State’s acknowledgement of responsibility, the Court finds that it has been proved that the State failed to comply with the requirements of Article 8(1) of the Convention. 129. Consequently, and since the State has acknowledged the existence of a criminal structure that took part in the execution of Senator Cepeda Vargas, it only remains for the Court to examine the aspects where the dispute between the parties subsists; in particular, the alleged ineffectiveness of the disciplinary and administrative-law proceedings, the lack of due diligence in the criminal investigations, and the alleged obstacles to the investigation. 130. In order to guarantee the right of access to justice in the case of an extrajudicial execution, in which criminal proceedings play a vital role, other mechanisms, methods and proceedings available under domestic law182 may be useful or effective as complementary elements in order to establish the truth, determine the scope and dimensions of the State’s responsibility, and make integral reparation for the 181 182 Brief in answer to the application, para. 609. Principle 12 of Basic Principles and Guidelines on the Right to a Remedy and Reparation for Victims of Gross Violations of International Human Rights Law and Serious Violations of International Humanitarian Law (Resolution 60/147 adopted by the United Nations General Assembly on December 16, 2005).