from prosecution to a person who provides substantial cooperation in the investigation or prosecution of an offence covered by this Convention. 4. Protection of such persons shall be as provided for in article 24 of this Convention. 5. Where a person referred to in paragraph 1 of this article located in one State Party can provide substantial cooperation to the competent authorities of another State Party, the States Parties concerned may consider entering into agreements or arrangements, in accordance with their domestic law, concerning the potential provision by the other State Party of the treatment set forth in paragraphs 2 and 3 of this article. Article 27. Law enforcement cooperation 1. States Parties shall cooperate closely with one another, consistent with their respective domestic legal and administrative systems, to enhance the effectiveness of law enforcement action to combat the offences covered by this Convention. Each State Party shall, in particular, adopt effective measures: (a) To enhance and, where necessary, to establish channels of communication between their competent authorities, agencies and services in order to facilitate the secure and rapid exchange of information concerning all aspects of the offences covered by this Convention, including, if the States Parties concerned deem it appropriate, links with other criminal activities; (b) To cooperate with other States Parties in conducting inquiries with respect to offences covered by this Convention concerning: (i) The identity, whereabouts and activities of persons suspected of involvement in such offences or the location of other persons concerned; (ii) The movement of proceeds of crime or property derived from the commission of such offences; (iii) The movement of property, equipment or other instrumentalities used or intended for use in the commission of such offences; (c) To provide, when appropriate, necessary items or quantities of substances for analytical or investigative purposes; (d) To facilitate effective coordination between their competent authorities, agencies and services and to promote the exchange of personnel and other experts, including, subject to bilateral agreements or arrangements between the States Parties concerned, the posting of liaison officers; 29