141. More specifically, in cases involving the use of lethal force by State agents, the Court has written that “the general prohibition to arbitrarily deprive someone of his life, which state officials must observe, would be ineffective without proceedings to verify the legality of the lethal use of force by state officials.”216 142. Accordingly, the general obligation to guarantee rights “is particularly important in cases of the use of lethal force.”217In the words of the Court: Upon learning that firearms have been used by members of its security forces and that such use had lethal consequences, the State has the obligation to initiate, ex officio and without delay, a serious, independent, impartial and effective investigation.218 This obligation is a fundamental and determining element of the protection of the right to life, which is affected in such situations.219 143. In the same vein, the United Nations Special Rapporteur on Extrajudicial, Summary and Arbitrary Executions has written that: Human rights standards on the use of force derive from the understanding that the irreversibility of death justifies stringent safeguards for the right to life, especially in relation to due process. A judicial procedure, respectful of due process and arriving at a final judgment, is generally the sine qua non without which a decision by the State and its agents to kill someone will constitute an “arbitrary deprivation of life” and, thus violate the right to life”220 144. According to the holding of the Court, in order to comply with the duty to investigate a human rights violation with due diligence, States are obligated to act, as of the first stages of the proceeding, with the utmost urgency.221In this regard, the Commission and the Court have taken into consideration the United Nations Manual on Effective Prevention and Investigation of Extra-legal, Arbitrary and Summary Executions. Based on said Manual, the Court has specifically noted, for example, that: [… continuation] [54] The Inter-American Court has held, for example, that “The American Convention guarantees everyone access to justice to enforce their rights, and the States Parties have the obligation to prevent, investigate, identify and punish the masterminds and accessories of human rights violations. “ IA Court of HR, Case of the Constitutional Court, judgment of September29, 1999. Series C Nº 71, para. 123. Also see I/A Court HR., Case of Blake v Guatemala, Reparations, Judgment of January 22, 1999, Series C Nº 48, paras. 65. 216I/A Court H.R., Case of Zambrano Vélez et al v. Ecuador. Merits, Reparations and Costs. Judgment of July 4, 2007. Series C No. 166, para. 88. Citing I/A Court H.R., Case of Montero Aranguren et al (Detention Center of Catia) v. Venezuela. Preliminary Objection, Mertis, Reparations and Costs. Judgment of July 5, 2006. Series C No. 150, paras. 79 – 83. 217I/A Court H.R., Case of Zambrano Vélez et al v. Ecuador. Merits, Reparations and Costs. Judgment of July 4, 2007. Series C No. 166, para. 88. 218I/A Court H.R., Case of Zambrano Vélez et al v. Ecuador. Merits, Reparations and Costs. Judgment of July 4, 2007. Series C No. 166, par. 88. Citing. 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, para. 112. Also see: I/A Court H.R., Case of the Miguel Castro Castro Prison, Merits, Reparations and Costs. Judgment of November 25, 2006. Series C No. 160, par. 256, and I/A Court H.R., Case of Vargas Areco, Merits, Reparations and Costs. Judgment of September 26, 2006. Series C No. 155, para. 77. Likewise, also see: ECHR, Erdogan and Others v. Turkey, paras. 88-89; ECHR, Kakoulli v. Turkey, Application No. 385/97. November 22, 2005, paras. 122-123, and ECHR, Nachova and Others v. Bulgaria [GC], nos. 43577/98 and 43579/98, paras. 111-112, 6 July 2005. 219I/A 166, par. 88. Court H.R., Case of Zambrano Vélez et al v. Ecuador. Merits, Reparations and Costs. Judgment of July 4, 2007. Series C No. 220Cfr. Provisional report on the global situation of extrajudicial, summary or arbitrary executions, submitted by the Special Rapporteur Philip Alston. United Nations General Assembly. (Doc. A/61/311), 59th Session, September 5, 2006, para. 36. 221I/A Court H.R., Case of Zambrano Vélez et al v. Ecuador. Merits, Reparations and Costs. Judgment of July 4, 2007. Series C No. 166, par. 121.