A U.S. agent who investigated a massacre at two villages in Afghanistan last March says the Ohio soldier charged in the killings had taken steroids.Matthew Hoffman of the Army's Criminal Investigation Division testified Wednesday Staff Sergeant Robert Bales tested positive for steroids three days after the killings. 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.