A Fort Hood official says there is a "strong possibility" that the gunman who killed three people and wounded 16 others at the Texas military base argued with one or more soldiers immediately before the shooting.
Fort Hood's senior officer, Lt. Gen. Mark Milley, said Thursday that investigators are looking into whether Spc. Ivan Lopez had a "verbal altercation" with another soldier or soldiers before Wednesday's shooting.
The soldier is identified by others as Ivan Lopez. He enlisted in the Army in June 2008 as an infantryman and later switched his specialty to truck driver, the job he had in Iraq.
Army Secretary John McHugh testified Thursday that the soldier appeared to have no connections to extremist groups.
The Army's top civilian official says the soldier accused in the Fort Hood shooting this week was deployed for the final months of the Iraq war but did not see combat.
McHugh says the soldier was examined by a psychiatrist last month and was found to show no violent or suicidal tendencies. He says the soldier had been prescribed Ambien to deal with a sleeping problem.