Riverside, Calif. ? A former Marine sergeant has been charged with voluntary manslaughter in the killings of two captured Iraqi insurgents in Fallujah in 2004.

Head shaven and wearing a black suit with an American flag pin on the lapel, Jose Nazario, 27, answered procedural questions before U.S. Magistrate Judge Oswald Parada. Bail was set at $50,000.

“He absolutely maintains his innocence,” defense attorney Emery Ledger said before the hearing. “He will be entering a not guilty plea.”

Nazario faces 10 years in prison if convicted of voluntary manslaughter, said Assistant U.S. Attorney Jerry Behnke.

The Navy has been investigating claims that Camp Pendleton Marines killed unarmed suspected Iraqi insurgents who had been captured during a fierce battle in Fallujah. The probe centers on the actions of several former members of 3rd Squad, 3rd Platoon, Kilo Company, 3rd Battalion, 1st Marines.

Nazario was squad leader. Because he is no longer in the military, his case is being handled in federal court.

According to his attorneys, Nazario completed two four-year enlistments after entering the Marine Corps in 1997.

According to a Naval Criminal Investigative Service criminal complaint supplied by Ledger, the killings occurred Nov. 9, 2004. The complaint says several Marines, whose names are redacted, allege Nazario shot two Iraqi men who had been detained while his squad searched a house.