Related Rule
Singapore
Practice Relating to Rule 158. Prosecution of War Crimes
Singapore’s Geneva Conventions Act (1973) provides:
1) Any person, whatever his citizenship or nationality, who, whether in or outside Singapore, commits, aids, abets or procures the commission by any other person of any such grave breach of any [of the 1949 Geneva Conventions] shall be guilty of an offence under this Act and on conviction thereof … [be punished].
(2) In the case of an offence under this section committed outside Singapore, a person may be proceeded against, charged, tried and punished therefor in any place in Singapore as if the offence had been committed in that place, and the offence shall, for the purposes incidental to or consequential on the trial or punishment thereof, be deemed to have been committed in that place. 
Singapore, Geneva Conventions Act, 1973, Section 3(1) and (2).