The shooter who killed three people at Fort Hood on Wednesday before turning the gun on himself suffered from mental health issues, according to the base commander.
"We do not know a motive. We do know that this soldier had behavior health and mental health issues and was being treated for that," he said during a press conference Wednesday night.
Sixteen other people were injured in the shooting, according to authorities.
No motive had yet been identified. Milley said there was no early indication of a link to terrorism but nothing could be ruled out. Law enforcement officials were digging deep into the shooter’s background, he said.
The gunman was suffering from depression and anxiety, according to the commander. He had been on medication.
When asked if the shooting revealed gaps in the military's treatment of mental health, Milley said, "We'll have to reexamine all of those programs and see if there were any gaps. So I'm not ready to answer that just yet."
There were also reports that the shooter had self-diagnosed himself with having a brain injury after returning home from Iraq in 2011, Milley said.
The shooter was identified as Ivan Lopez, according to House Homeland Security Committee Chairman Michael McCaul (R-Texas). Fort Hood did not release his name because his family had not been notified.
Milley said the shooter was married and had a family.
The shooter served a four-month tour of duty in Iraq in 2011. He had not been wounded while there, Milley said. He had recently been transferred to Fort Hood from another installation.
The shooting incident began in the late afternoon on the Texas base.
At 6:30 p.m. ET, Fort Hood sent out a statement that a shooting had been reported there and emergency crews were responding. It advised personnel on the base to shelter in place.
The shooter entered a building with a .45 caliber semi-automatic handgun on the base and began firing. He then got in a vehicle and moved to another building.
After being confronted by an officer on a base parking lot, the shooter put his hands up before reaching down for his gun and turning it on himself.