There were. One of the more famous incidents is a massacre that took place in southern Sicily in July 1943. Soldiers from the 180th Infantry Regiment killed 73 unarmed Italian and German POWs captured during the battle for Biscari Airfield.

Gen. Omar Bradley informed Gen. George Patton about the massacres, and Patton noted it in his diary:

"I told Bradley that it was probably an exaggeration, but in any case to tell the officer to certify that the dead men were snipers or had attempted to escape or something, as it would make a stink in the press and also would make the civilians mad. Anyhow, they are dead, so nothing can be done about it."

Bradley ignored Patton's suggestions, and Patton appears to have changed his mind (according to his diary) after he learned more details of the massacre. The U.S. Army charged Sgt. Horace West with "willfully, deliberately, feloniously, unlawfully" killing prisoners of war. West, in a court-martial, was found guilty of premeditated murder. He was stripped of his rank and sentenced to life in jail. In November 1944, however, he was freed from jail and restored to active duty, where he served without incident until the end of the war and was granted an honorable discharge.

This odd end to a conviction came because of actions by Gen. Eisenhower, who reviewed the case after the sentence was handed down. If West were sent to federal prison in the United States, it likely would become public knowledge. If he were kept confined in North Africa, the case could be kept under wraps. Eisenhower "feared reprisal to Allied prisoners" if the case were made public, wrote Harry Butcher, Eisenhower's naval aide, in his diary.

Capt. John Compton, commander of C Company, 1st Battalion of the 180th, was also court-martialed but was acquitted of murdering POWs. He was transferred and killed in action in November 1943 in Italy.

During the trials, West and his regimental commander said they had heard Gen. Patton say that if the Italians and Germans continued to resist after U.S. soldiers came within 200 yards, the Americans need not take prisoners.

The investigation cleared Patton of any wrongdoing, and I can find no reference in Patton's diary to such a speech.