Related Rule
Croatia
Practice Relating to Rule 65. Perfidy
Section B. Killing, injuring or capturing an adversary by resort to perfidy
Under Croatia’s Criminal Code (1997), if the killing of an enemy who has laid down arms or has surrendered at discretion, or has no longer any means of defence, is committed in a “treacherous way”, this constitutes an aggravating circumstance of the war crime. 
Croatia, Criminal Code, 1997, Article 161(2).