The soldier who killed three people before committing suicide in an attack on the same Texas military base where more than a dozen people were shot dead in 2009 had shown no recent risks of violence, officials say.
The shooter, identified as Ivan Lopez by Texas Rep Michael McCaul, chairman of the House Homeland Security Committee, opened fire at Fort Hood yesterday.
He wounded more than a dozen others.
Military officials declined to formally identify the gunman, an enlisted soldier with the rank of specialist, by name until his family members had been officially notified.
But Army Secretary John McHugh said the soldier saw no combat during a four-month deployment to Iraq as a truck driver from August to December 2011. A review of his service record showed no Purple Heart, which indicates he was never wounded.
The soldier saw a psychiatrist last month and showed no “sign of any likely violence either to himself or others,” McHugh said.
His record shows “no involvement with extremist organisations of any kind.”
“We’re not making any assumptions by that. 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 behaviour,” Mr McHugh said.
Within hours of the attack, investigators started looking into whether the soldier had lingering psychological trauma from his time in Iraq.
Fort Hood’s senior officer, Lt Gen Mark Milley, said the gunman had sought help for depression, anxiety and other problems, and was taking medication.
Among the possibilities investigators were exploring was whether a fight or argument on the base triggered the attack.
“We have to find all those witnesses, the witnesses to every one of those shootings, and find out what his actions were, and what was said to the victims,” said a federal law enforcement official.
He said authorities would begin by speaking with the man’s wife, and expected to search his home and any computers he owned.
Lopez apparently walked into a building and began firing a .45-calibre semi-automatic pistol. He then got into a vehicle and continued firing before entering another building, but he was eventually confronted by military police in a car park, according to Lt Gen Milley.
As he came within 20 feet (six metres) of an officer, the gunman put his hands up but then reached under his jacket and pulled out his gun. The officer drew her own weapon, and the suspect put his gun to his head and pulled the trigger a final time, Lt Gen Milley said.
His weapon was recently bought locally and was not registered to be on the base.
Mr McHugh said the soldier, a Puerto Rico native, joined the island’s National Guard in 1999 and served on a year-long peace-keeping mission in Egypt’s Sinai Peninsula in the mid-2000s. He then enlisted with the Army in 2008.
Those injured were taken to the base hospital and other local hospitals. At least three of the nine patients were still listed in critical condition today.
The shootings immediately revived memories of the 2009 shooting rampage on Fort Hood, the deadliest attack on a domestic military installation in US history. Thirteen people were killed and more than 30 were wounded.
Army psychiatrist Nidal Hasan was convicted last year for the mass shooting.
According to trial testimony, he walked into a crowded building, shouted “Allahu Akbar!” – Arabic for “God is great!” – and opened fire.
The rampage ended when Hasan was shot in the back by base police officers.
Hasan, now paralysed from the waist down, is on death row at the military prison at Fort Leavenworth in Kansas. He has said he acted to protect Islamic insurgents abroad from American aggression.
After that shooting, the military tightened base security nationwide. That included issuing security personnel long-barrelled weapons, adding an insider-attack scenario to their training, and strengthening ties to local law enforcement.
The military also joined an FBI intelligence-sharing programme aimed at identifying terror threats.
In September, a former Navy man opened fire at the Washington Navy Yard, leaving 13 people dead, including the gunman.
After that shooting, Defence Secretary Chuck Hagel ordered the Pentagon to review security at all US defence installations worldwide and examine the granting of security clearances that allow access to them.