Chapter IV
Fundamental Rights

36. (8) No person shall be held to be guilty of a criminal offence on account of any act or omission that did not, at the time it took place, constitute such an offence, and no penalty shall be imposed for any criminal offence heavier than the penalty in force at the time the offence was committed.

Chapter IV
Fundamental Rights

36. (12) Subject as otherwise provided by this Constitution, a person shall not be convicted of a criminal offence unless that offence is defined and the penalty therefor is prescribed in a written law, and in this subsection, a written law refers to an Act of the National Assembly or a Law of a State, any subsidiary legislation or instrument under the provisions of a law.

Article 22
Nullum crimen sine lege
1. A person shall not be criminally responsible under this Statute unless the conduct in question constitutes, at the time it takes place, a crime within the jurisdiction of the Court.
2. The definition of a crime shall be strictly construed and shall not be extended by analogy. In case of ambiguity, the definition shall be interpreted in favour of the person being investigated, prosecuted or convicted.
3. This article shall not affect the characterization of any conduct as criminal under international law independently of this Statute.