25. The petitioners are authorized, in principle, by Article 44 of the American Convention to submit complaints to the IACHR. The petition identifies as the alleged victims individual persons with respect to whom Colombia undertook to respect and ensure the rights enshrined in the American Convention. As regards the State, the Commission notes that Colombia has been a State Party to the American Convention since July 31, 1973, when the instrument of ratification was deposited. Accordingly, the Commission is competent ratione personae to examine the petition. 26. The Commission is competent ratione loci to take cognizance of the petition insofar as it alleges violations of rights protected in the American Convention in the territory of a State party to that treaty. The IACHR is competent ratione temporis since the obligation to respect and ensure the rights protected in the American Convention was already in force for the State at the date when the incidents are alleged to have occurred. Finally, the Commission is competent ratione materiae because the petition alleges violations of human rights protected by the American Convention. B. Admissibility Requirements a. Exhaustion of domestic remedies and time period for submitting the petition 27. The State alleges that the petition does not satisfy the requirement of prior exhaustion of domestic remedies provided for at Article 46(1)(a) of the American Convention. This assertion appears in its communication of March 5, 2001 submitted approximately three years after the processing of this matter began, on April 1, 1998. The petitioners, for their part, allege that the exception to the prior exhaustion requirement set forth at Article 46(2)(c) applies, due to the unwarranted delay in the investigation and to the indicia of impunity surrounding this matter. In this sense, the State alleges that the time invested in clarifying the violations denounced is reasonable in view of the complexity of the matter and the way in which the evidence was produced in this case. 28. Article 46(1)(a) of the American Convention requires the prior exhaustion of domestic remedies, in keeping with the general principles of international law. In this regard, the caselaw of the Inter-American Court of Human Rights indicates that the rule of prior exhaustion of domestic remedies is designed to benefit the State, and therefore the State can waive this objection, expressly or tacitly. It follows that in order that it not be presumed that the State has tacitly waived this objection, it must be expressly and timely invoked in the first stages of the proceeding before the Commission.13 Based on the case-law of the Inter-American Court, the mere submission of information on progress in domestic judicial proceedings is not equivalent to expressly invoking the requirement of prior exhaustion of domestic remedies.14 29. In the instant case, the Commission notes that the State did not object to the failure to exhaust domestic remedies at the first procedural opportunity available; it was not until its brief of March 5, 2001 that it expressly raised the failure to abide by Article 46(1)(a). In light of the case-law described and the late invoking of the failure to exhaust domestic remedies as grounds of inadmissibility, the State is considered to have tacitly waived this objection. 30. Without prejudice to the application of the rules regarding a tacit waiver, and given the characteristics of the case, the IACHR takes this opportunity to set forth a series of considerations with regard to the parties’ allegations in relation to Article 46(2) of the Convention, in light of the principle by which a state that invokes the requirement in question must identify the domestic remedies to be exhausted and show that they are effective.15 13 I/A Court H.R., Castillo Páez Case, Preliminary Objections, Judgment of January 30, 1996 para. 40; Loayza Tamayo Case, Preliminary Objections, Judgment of January 31, 1996 para. 40; Castillo Petruzzi Case, Preliminary Objections, Judgment of September 4, 1998 para. 56; Mayagna (Sumo) Community of Awas Tingni, Preliminary Objections, Judgment of February 1, 2000 para. 54. 14 I/A Court H.R., Mayagna (Sumo) Community of Awas Tingni, Preliminary Objections, Judgment of February 1, 2000 paras. 55 and 56. 15 I/A Court H.R., Castillo Páez Case, Preliminary Objections, Judgment of January 30, 1996 para. 40; Loayza Tamayo Case, Preliminary Objections, Judgment of January 31, 1996 para. 40; Cantoral Benavides Case, Preliminary 6