73 substantive right that must be ensured, protected and guaranteed.297 In addition, Mexico must comply with the provisions of Article 7(b) and 7(c) of the Convention of Belém do Pará, which establishes the obligation to act with due diligence,298 and to adopt the necessary laws to investigate and to punish violence against women. 288. In its judgment on merits in the case of Velásquez Rodríguez v. Honduras, the Court established that, pursuant to the obligation to guarantee: The State is obligated to investigate every situation involving a violation of the rights protected by the Convention. If the State apparatus acts in such a way that the violation goes unpunished and the victim's full enjoyment of such rights is not restored as soon as possible, the State has failed to comply with its duty to ensure the free and full exercise of those rights to the persons within its jurisdiction. The same is true when the State allows private persons or groups to act freely and with impunity to the detriment of the rights recognized by the Convention.299 289. The duty to investigate is an obligation of means and not of results, which must be assumed by the State as an inherent legal obligation and not as a mere formality preordained to be ineffective.300 The State’s obligation to investigate must be complied with diligently in order to avoid impunity and the repetition of this type of act. In this regard, the Tribunal recalls that impunity encourages the repetition of human rights violations.301 290. In light of this obligation, as soon as State authorities are aware of the fact, they should initiate, ex officio and without delay, a serious, impartial and effective investigation using all available legal means, aimed at determining the truth and the pursuit, capture, prosecution and eventual punishment of all the perpetrators of the facts, especially when public officials are or may be involved.302 291. Moreover, the Court has noted that this obligation remains “whatsoever the agent to which the violation may eventually be attributed, even individuals, because, if their acts are not investigated genuinely, they would be, to some extent, assisted by the public authorities, which would entail the State’s international responsibility.”303 292. In this regard, within the framework of the obligation to protect the right to life, the European Court of Human Rights has developed the concept of the “procedural obligation” to carry out an effective official investigation in cases of the violation of that right.304 The Inter-American Court has also applied this concept in several cases.305 297 Cf. Case of the Pueblo Bello Massacre v. Colombia, supra note 261, para. 142; Case of Heliodoro Portugal v. Panamá. Preliminary Objections, Merits, Reparations and Costs. Judgment of August 12, 2008. Series C No. 186, para. 115, and Case of Perozo et al. v. Venezuela, supra note 22, para. 298. 298 Cf. Case of the Miguel Castro Castro Prison v. Peru, supra note 248, para. 344. 299 Case of Velásquez Rodríguez v. Honduras. Merits, supra note 257, para. 176, and Case of Kawas Fernández v. Honduras, supra note 190, para. 76. 300 Cf. Case of Anzualdo Castro v. Peru, supra note 30, para. 123, and Case of Garibaldi v. Brazil, supra note 252, para. 113. 301 Cf. Case of Anzualdo Castro v. Peru, supra note 30, para. 179, and Case of Garibaldi v. Brazil, supra note 252, para. 141. 302 Cf. Case of the Pueblo Bello Massacre v. Colombia, supra note 261, para. 143; Case of Heliodoro Portugal v. Panamá, supra note 297, para. 144, and Case of Valle Jaramillo et al. v. Colombia, supra note 49, para. 101. 303 Case of the Pueblo Bello Massacre v. Colombia, supra note 261, para. 145, and Case of Kawas Fernández v. Honduras, supra note 190, para. 78. 304 Cf. ECHR, Ergi v. Turkey, Judgment of 28.07(1)998, Reports of Judgments, n. 81, paras. 85-86, and ECHR, Akkoç v. Turkey, Judgment of 10 October 2000, paras. 77 to 99; ECHR, Kiliç v. Turkey, Judgment of 28 March 2000, paras. 78 to 83.