Army searches for motive in Fort Hood attack

UPDATE (5:30 P.M. EDT): Army officials have now confirmed the identity of the soldier who opened fire at Fort Hood yesterday, killing three people and injuring about a dozen more. Spc. Ivan Lopez, 34, enlisted in the Army in 2008 after spending almost 10 years in the National Guard in Puerto Rico.

Army officials have also confirmed that they are investigating the strong possibility that a verbal altercation with one or more soldiers might have triggered Lopez's attack.

EARLIER STORY: U.S Army investigators are once again trying to piece together the motives of a soldier who opened fire Wednesday at Fort Hood, the massive military base in Killeen, Texas, where another deadly shooting left 13 people dead in 2009.

Four people, including the gunman, died in Wednesday’s attack, and a dozen more were injured. Early reports described the gunman as an Iraq war veteran suffering from post-traumatic stress disorder and possibly a traumatic brain injury. Army officials, who have not identified the gunman by name, now say the soldier spent about four months in Iraq at the end of 2011, but never saw combat and was never injured.

Speaking to members of the Senate Armed Services Committee, Secretary of the Army John McHugh said the soldier saw a psychiatrist last month, but showed no “sign of any likely violence either to himself or others.” McHugh also said the Army had no record of any involvement by the soldier with extremist groups, though investigators will not rule out anything as they search for a motive for the attack.

“We’re not making any assumptions by that,” McHugh said. “We’re going to keep an open mind and an open investigation. We will go where the facts lead us. And possible extremist involvement is still being looked at very, very carefully. He had a clean record in terms of his behavior.”

Fort Hood’s senior officer, Lt. Gen. Mark Milley, said the gunman sought help for depression, anxiety, and other problems and was taking medication. Investigators also are looking into the possibility that a problem with someone at the base might have triggered the violence.

Late Wednesday afternoon, the gunman walked into a building and began firing a .45-caliber semi-automatic handgun at other soldiers. As he left the building, he continued to fire from inside a vehicle before stopping at another building, going inside, and shooting some more. A military police officer eventually confronted him in a parking lot. He appeared at first ready to surrender, putting his hands up in the air. But before the officer could approach him, the soldier pulled a gun out of his jacket and shot himself in the head.

Investigators are interviewing the soldier’s wife, who moved to Killeen with her husband from Fort Bliss, in El Paso, Texas, in February. They’re also talking to witnesses to help piece together his movements and interactions in the last few days and weeks.

Four and a half years ago, Maj. Nidal Hasan opened fire in a crowded building on base, killing 13 and wounding more than 30. A military jury convicted him of the mass shooting last year and sentenced him to death. Hasan said his attack was in retaliation for U.S. military aggression toward Muslims in Iraq and Afghanistan. News reports said today that Wednesday’s gunman bought his .45-caliber semi-automatic at the same Killeen store where Hasan purchased an FN 5-7 tactical pistol used in the 2009 rampage.

The Associated Press contributed to this report.