RIVERSIDE, Calif. (AP) — A former Marine accused of killing unarmed Iraqi detainees was acquitted of voluntary manslaughter Thursday in a first-of-its-kind federal trial that ended with some of the jurors shaking hands and hugging the defendant and his sobbing mother.

The jury took less than six hours to find Jose Luis Nazario Jr. not guilty of charges that he killed or caused others to kill four unarmed detainees on Nov. 9, 2004, in Fallujah, Iraq, during some of the fiercest fighting of the war.

The verdict left the 28-year-old defendant — and some of the jurors — in tears. His mother, family and friends cried so loud the judge smacked his gavel in a call for order.

Thursday's verdict marks the first time a civilian jury has determined whether the alleged actions of a former military service member in combat violated the law of war.