Any person subject to this code who, while in the hands of the enemy, in time of war: (1) For the purpose of securing favorable treatment by his captors acts without proper authority in a manner contrary to law, custom or regulation, to the detriment of others of whatever nationality held by the enemy as civilian or military prisoners, or (2) while in a position of authority over such persons, maltreats them without justifiable cause shall be punished as a court-martial may direct.