1. Each State Party shall take appropriate measures to encourage persons who participate or who have participated in organised criminal groups:
(a) to supply information useful to competent authorities for investigative and evidentiary purposes on such matters as:
(i) the identity, nature, composition, structure, location or activities of organised criminal groups;
(ii) links, including international links, with other organised criminal groups;
(iii) offences that organised criminal groups have committed or may commit;
(b) to provide factual, concrete help to competent authorities that may contribute to depriving organised criminal groups of their resources or of the proceeds of crime.
2. Each State Party shall consider providing for the possibility, in appropriate cases, of mitigating punishment of an accused person who provides substantial cooperation in the investigation or prosecution of an offence covered by this Convention.
3. Each State Party shall consider providing for the possibility, in accordance with fundamental principles of its domestic law, of granting immunity 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.