alleged acts began, the obligation to respect and guarantee the rights protected in the American Convention was already in effect in the State of Mexico. B. Other admissibility requirements 1. Exhaustion of domestic remedies 39. Article 46(1) of the American Convention establishes that in order for a complaint to be admissible pursuant to the terms of Article 44 of the Convention, the petitioners must have exhausted domestic remedies, in accordance with the generally recognized principles of international law. This requirement has been consistently upheld as a procedural requirement in the Commission’s jurisprudence, because it permits states to take cognizance of alleged violations of a right protected by the American Convention, and if relevant, it gives them an opportunity to rectify them in their courts, before the intervention of the subsidiary jurisdiction of an international body. 40. The IACHR observes that in the case in point, the petitioners filed a writ of amparo or constitutional protection of rights on March 17, 1999, registered as No. 238/99. That writ was not allowed, pursuant to the decision of March 31, 1999, on the grounds that the petitioners did not indicate the place where the directly injured party was being held. 53 The petitioners also lodged a complaint with the Ministerio Público. 41. With regard to the amparo writ, the IACHR notes that it was filed for the purpose of learning the whereabouts of the alleged victim, since in the Mexican legal system, a writ of amparo is equivalent to a writ of habeas corpus. The InterAmerican Court has maintained that “exhibition of the person or habeas corpus is normally the adequate [recourse] for finding a person detained by the authorities, determining if the person is being held legally, and, if applicable, providing for his or her release [...].” 54 In such circumstances, habeas corpus performs a critical function in a case of forced disappearance, since “it can be an effective recourse for locating the whereabouts of a person or clarifying if there is a situation injurious to a person’s freedom, despite the fact that the person in whose favor the writ is filed is not in the custody of the State, but has instead been placed in the custody of an individual, or despite the fact that a long period of time has elapsed since the person disappeared.” 55 42. However, the petitioners also lodged a complaint with the Ministerio Público; here, reference should be made to the pretrial investigation opened in response to that complaint on January 24, 1999. According to both parties, that investigation is still open, in a preliminary stage, eight years following the disappearance of Antonio González Méndez, without producing conclusive results on the possible whereabouts of Mr. González Méndez and the possible motives of his disappearance. 43. On this point, the IACHR notes that the rule of exhaustion of domestic remedies has exceptions established in Article 46(2), which states that this rule is not applicable when the domestic legislation does not have a remedy for protection of the right recognized in the American Convention, or if the alleged victim was denied access to the domestic remedies, or if there was an unwarranted delay in rendering a judgment under said remedy. Article 31(3) of the Commission’s Rules of Procedure stipulates that when the petitioner alleges one of the exceptions to the rule of 53 Writ of amparo 238/99, Resolution of March 31, 1999. 54 I/A Court H.R., Velásquez Rodríguez Case. Judgment of July 29, 1988. Series C, No.4, para. 65. 55 I/A Court H.R., Case of the Serrano Cruz Sisters. Judgment of March 1, 2005. Series C, No. 120, para. 79. 10