3. This Convention does not exclude any additional criminal jurisdiction exercised in accordance with national law. Article 10 1. Upon being satisfied, after an examination of the information available to it, that the circumstances so warrant, any State Party in whose territory a person suspected of having committed an offence of enforced disappearance is present shall take him or her into custody or take such other legal measures as are necessary to ensure his or her presence. The custody and other legal measures shall be as provided for in the law of that State Party but may be maintained only for such time as is necessary to ensure the person’s presence at criminal, surrender or extradition proceedings. 2. A State Party which has taken the measures referred to in paragraph 1 of this article shall immediately carry out a preliminary inquiry or investigations to establish the facts. It shall notify the States Parties referred to in article 9, paragraph 1, of the measures it has taken in pursuance of paragraph 1 of this article, including detention and the circumstances warranting detention, and of the findings of its preliminary inquiry or its investigations, indicating whether it intends to exercise its jurisdiction. 3. Any person in custody pursuant to paragraph 1 of this article may communicate immediately with the nearest appropriate representative of the State of which he or she is a national, or, if he or she is a stateless person, with the representative of the State where he or she usually resides. Article 11 1. The State Party in the territory under whose jurisdiction a person alleged to have committed an offence of enforced disappearance is found shall, if it does not extradite that person or surrender him or her to another State in accordance with its international obligations or surrender him or her to an international criminal tribunal whose jurisdiction it has recognized, submit the case to its competent authorities for the purpose of prosecution. 2. These authorities shall take their decision in the same manner as in the case of any ordinary offence of a serious nature under the law of that State Party. In the cases referred to in article 9, paragraph 2, the standards of evidence required for prosecution and conviction shall in no way be less stringent than those which apply in the cases referred to in article 9, paragraph 1. 3. Any person against whom proceedings are brought in connection with an offence of enforced disappearance shall be guaranteed fair treatment at all stages of the proceedings. Any person tried for an offence of enforced disappearance shall benefit from a fair trial before a competent, independent and impartial court or tribunal established by law. Article 12 1. Each State Party shall ensure that any individual who alleges that a person has been subjected to enforced disappearance has the right to report the facts to the competent authorities, which shall examine the allegation promptly and impartially and, where necessary, undertake without delay a thorough and impartial investigation. Appropriate steps shall be taken, where necessary, to ensure that the complainant, witnesses, relatives of the disappeared person and their defence counsel, as well as persons participating in the investigation, are protected against all ill-treatment or intimidation as a consequence of the complaint or any evidence given. 2. Where there are reasonable grounds for believing that a person has been subjected to enforced disappearance, the authorities referred to in paragraph 1 of this article shall undertake an investigation, even if there has been no formal complaint. 3. Each State Party shall ensure that the authorities referred to in paragraph 1 of this article: (a) Have the necessary powers and resources to conduct the investigation effectively, including access to the documentation and other information relevant to their investigation;