Updated

A U.S. Army DNA expert says the soldier suspected of killing 16 Afghan civilians during a nighttime rampage last March had the blood of at least four people on his clothes and guns when he surrendered.

Christine Trapolsi, an examiner at the Army's Criminal Investigations Lab, says the blood of two males and two females were discovered on Staff Sgt. Bales' pants, gloves, rifle and other items. She says she only tested a small portion of the bloodstains, and it's possible more DNA profiles could be discovered with additional testing.

She testified Thursday at a preliminary hearing in Bales' case. The hearing at Joint Base Lewis-McChord south of Seattle will help determine whether Bales' case advances to a court martial.

Afghan villagers and soldiers are expected to testify by video from Afghanistan Friday and Saturday nights.