Part VI
Mutual legal assistance in criminal matters
CHAPTER III
Special forms of international assistance
Article 156
Temporary transfer of persons in custody for purposes of investigation
1. The provisions of Article 155 shall apply to cases in which, upon agreement, a person arrested or imprisoned in Portugal may be temporarily transferred to the territory of another State for purposes of investigation in the framework of Portuguese criminal proceedings.
2. The agreement mentioned in paragraph 1 above shall not be required where the transfer is made under an international agreement, treaty or convention that does not impose it.
3. The provisions of the preceding paragraph shall apply mutatis mutandis to requests of assistance submitted to Portugal.
Person sought for different crime
Temporary transfer of persons in custody for purposes of identification or for obtaining testimony or other forms of assistance - authority - ICC proceedings
EDIT.