8. General restrictions on return.

(2) A person accused of an offence shall not be returned under this Act, other than under section 11, to a declared Commonwealth or foreign territory, or committed to or kept in custody for the purposes of the return, if it appears as aforesaid that if charged with that offence in Trinidad and Tobago he would be entitled to be discharged under any rule of law relating to previous acquittal or conviction.

Article 20
Ne bis in idem
1. Except as provided in this Statute, no person shall be tried before the Court with respect to conduct which formed the basis of crimes for which the person has been convicted or acquitted by the Court.
2. No person shall be tried by another court for a crime referred to in article 5 for which that person has already been convicted or acquitted by the Court.
3. No person who has been tried by another court for conduct also proscribed under article 6, 7 or 8 shall be tried by the Court with respect to the same conduct unless the proceedings in the other court:
(a) Were for the purpose of shielding the person concerned from criminal responsibility for crimes within the jurisdiction of the Court; or
(b) Otherwise were not conducted independently or impartially in accordance with the norms of due process recognized by international law and were conducted in a manner which, in the circumstances, was inconsistent with an intent to bring the person concerned to justice.