Answer
Peiper was convicted of participating in the Malmedy massacre, in which 84 American prisoners of war were killed. The massacre was committed by a Waffen-SS unit under Peiper's command in the Ardennes Offensive in December 1944. Peiper was found guilty of war crimes and sentenced to death, but his sentence was commuted to life imprisonment. He was released from prison in 1956 and died in 1976.