- 54 - 152. Furthermore, as established by domestic authorities216 and as recognized by the State,217 the said sergeants took part in the murder of a lieutenant on July 14, 1999, while they were deprived of liberty on military premises. The Court notes that, when the application of benefits during execution of sentence was being assessed, the acknowledged fact that, while deprived of liberty, they had left the military detention center218 and taken part in the said operation219 was not taken into consideration. The undue granting of such benefits could eventually lead to a form of impunity, particularly in cases of the perpetration of serious human rights violations, as in the instant case.220 In addition, it has been verified that the convicted men served part of their sentence, exactly one year, three months and 18 days, in the Tolemaida Military Rehabilitation Center in Melgar, Tolima – intended for soldiers serving sentences for infringing the Military Criminal Code – even though, the military jurisdiction “should only prosecute members of the armed forces for committing crimes or misdemeanors that, by their nature, impair the legal interests of the military system,”221 a principle that is also applicable at the stage of execution of judgment.222 153. In this regard, the Court considers it pertinent to reiterate that proceedings followed through up until their conclusion and that fulfill their purpose are the clearest sign of zero tolerance for human rights violations, contribute to the reparation of the victims, and show society that justice has been done.223 The imposing of an appropriate punishment duly founded and proportionate to the seriousness of the facts, by the competent authority,224 permits verification that the sentence imposed is not arbitrary, thus ensuring that it does not become a type of de facto impunity.225 In this regard, the Court has emphasized that administrative or criminal sanctions play an 216 Record of a visit in case file No. 020-76-840-02 issued by the office of the Attorney delegated to the National Police on December 6, 2002 (evidence file, tome IX, attachment 144 to the brief with pleadings, motions and evidence, folios 4442 to 4445). 217 Cf. oral arguments of the State during the public hearing held before the Inter-American Court on January 26, 2010, and final written arguments of the State, p. 30. 218 They were interned in the barracks of the XIII Battalion, to which they belonged. 219 Cf. Sole instance ruling by the Vice President of the office of the Attorney General of the Nation in Investigation No. 002-61126-02 on February 27, 2004, supra note 141, folios 4439 to 4492. 220 Cf. Gómez Paquiyauri Brothers v. Peru. Merits, reparations and costs. Judgment of July 8, 2004. Series C No. 110, para. 145. 221 Castillo Petruzzi et al. v. Peru. Preliminary objections. Judgment of September 4, 1998. Series C No. 41, para. 128; Case of Radilla Pacheco v. Mexico, supra note 24, para. 272; Case of Durand and Ugarte v. Peru, supra note 34, para. 117; Cantoral Benavides v. Peru. Merits. Judgment of August 18, 2000. Series C No. 69, para. 112; Case of Las Palmeras v. Colombia, supra note 32, para. 51; 19 Tradesmen v. Colombia. Merits, reparations and costs. Judgment of July 5, 2004. Series C No. 109, para. 165; Lori Berenson Mejía v. Peru. Merits, reparations and costs. Judgment of November 25, 2004. Series C No. 119, para. 142; Case of the Mapiripán Massacre v. Colombia. Merits, reparations and costs, supra note 22, para. 202; Palamara Iribarne v. Chile. Merits, reparations and costs. Judgment of November 22, 2005. Series C No. 135, paras. 124 and 132; Case of the Pueblo Bello Massacre v. Colombia, supra note 136, para. 189; Case of Almonacid Arellano et al. v. Chile, supra note 38, para. 131; Case of La Cantuta v. Peru, supra note 180, para. 142; Case of the La Rochela Massacre v. Colombia, supra note 16, para. 200; Case of Escué Zapata v. Colombia, supra note 16, para. 105, and Case of Tiu Tojín v. Guatemala, supra note 18, para. 118. 222 Cf. Barreto Leiva v. Venezuela. Merits, reparations and costs. Judgment of November 17, 2009. Series C No. 206, para. 29. 223 Cf. The “Street Children” (Villagrán Morales et al.) v. Guatemala. Monitoring compliance with judgment. Order of the Inter-American Court of Human Rights of January 27, 2009, para. 21. 224 225 Cf. Case of the La Rochela Massacre v. Colombia, supra note 16, para. 196. The Updated Set of Principles for the Protection and Promotion of Human Rights through Action to Combat Impunity establishes as one of the elements of impunity, the failure to “sentence to appropriate penalties” those found guilty of violations. Cf., also, Case of Heliodoro Portugal v. Panama, supra note 51, para. 203, in which the Court stated that: “it is necessary to avoid illusory measures that only appear to satisfy the formal requirements of justice.”