Updated

A U.S. agent who investigated a massacre at two Afghan villages last March says the soldier charged in the killings had taken steroids.

Special Agent Matthew Hoffman of the Army's Criminal Investigation Division testified at a hearing Wednesday that Staff Sgt. Robert Bales tested positive for steroids three days after the killings.

Hoffman also described the enraged reaction of Afghan villagers. He says the situation was so volatile that U.S. investigators couldn't get to the crime scene for three weeks. Even then, they were expecting to be ambushed.

Bales faces 16 counts of premeditated murder, six counts of attempted murder and a count of steroid use. The hearing will help determine whether his case advances to a court martial.