(3)A provost- marshal may act any time arrest and detain for trial any person subject to this Act who commits, or is charged with, an offence, and may also carry into effect any punishment to be inflicted in pursuance of the sentence awarded by a court-martial, or by an officer exercising authority under section 80 but shall not inflict any punishment on his own authority:Provided that no officer shall be so arrested or detained otherwise than on the order of another officer.
