 However, all members of the imperial family implicated in the war, such as Emperor Shōwa, were exonerated from criminal prosecutions by Douglas MacArthur.The Japanese military before and during World War II committed numerous atrocities against civilian and military personnel.Its surprise attack on Pearl Harbor on December 7, 1941, prior to a declaration of war and without warning killed 2,403 neutral military personnel and civilians and wounded 1,247 others.