newday Howell Fort Hood mass shooting wrap_00020121.jpg
Fort Hood shooter underwent treatment
02:04 - Source: CNN AP

Story highlights

Sgt. Timothy Owens was killed in the shooting, his family says

Gunman Ivan Lopez kills three people, wounds 16 others at the Army post

Commanding general: We believe psychiatric issues were a "causal factor"

U.S. Defense Secretary Chuck Hagel: "Obviously something went wrong"

Killeen, Texas CNN  — 

A man opens fire at a military base, gunning down fellow soldiers before ending his own life. A hero steps in, trying to stop him. A community already scarred by war is left reeling, nearly five years after authorities vowed to improve security when another mass shooter struck there.

A day after a shooting rampage at Fort Hood, Texas, left three soldiers dead and 16 wounded, a key question looms over the investigation: Why?

Authorities are still piecing together the answer, but seem to be homing in on at least one thing that they say might have made 34-year-old Spc. Ivan Lopez pull the trigger.

“We have very strong evidence that he had a medical history that indicates an unstable psychiatric or psychological condition. (We’re) going through all records to ensure that is, in fact, correct. But we believe that to be the fundamental underlying causal factor,” Lt. Gen. Mark Milley, the post’s commanding general, told reporters Thursday.

The rampage started around 4 p.m. Wednesday, when Lopez fired his .45-caliber handgun at two buildings at the sprawling Texas military facility. When a police officer confronted him later, he put the gun to his head and pulled the trigger, ending his life.

The gunman was an experienced soldier who was grappling with mental illness, officials said. But they haven’t pinpointed why he opened fire.

Authorities are interviewing witnesses and “looking at what the trigger event was” that led to the shooting, including a possible altercation with a fellow soldier “that immediately preceded the shooting,” Milley said.

Investigators say they haven’t found any links to domestic or international terrorist organizations, but they’re keeping open minds.

“At this point we have not yet ruled out anything whatsoever,” Milley said. “We are committed to letting the investigation run its course.”

Another key question for investigators: did any gaps in safety and security measures allow the shooting to take place?

“Obviously something went wrong,” U.S. Defense Secretary Chuck Hagel told reporters on Thursday.

But he stressed that investigators were still trying to piece together the events leading up to the shooting.

“We know a lot of things 24 hours later, but we don’t know everything,” Hagel said. “What happened? What motivated this person to do this? Where was the gap? Why did we have a gap? Why did it happen? … I think we are going to find out, and we will do everything possible to implement those reforms and fill those kinds of gaps.”

Lopez had a history of depression, anxiety

The native of Puerto Rico enlisted in the Army as an infantry soldier and was deployed twice, including a four-month stint in Iraq as a truck driver, Milley said.

He served in the National Guard in Puerto Rico from 1999 until 2010, when he left the Guard to become an active duty infantryman in the U.S. Army.

Before coming to Fort Hood, Lopez served at Fort Bliss in Texas.

Lopez arrived at the Fort Hood in February, moving with his wife and their daughter into an apartment a little more than a week before the shooting.

They appeared to be a normal couple, said neighbor Xanderia Morris. “They would smile whenever they’d see someone,” she said.

But behind Lopez’s smile lay a history of depression, anxiety and other psychiatric disorders, Milley told reporters. The soldier was receiving treatment and taking antidepressants, Milley said.

He had served for four months in Iraq in 2011. And while Army records don’t show him as having been wounded there, Lopez himself reported that he had suffered a traumatic brain injury, Milley said.

And he was undergoing diagnosis procedures for post-traumatic stress disorder.

“He was not diagnosed, as of today, with PTSD,” Milley said.

Arriving at a PTSD diagnosis, which is common among war veterans, can take time.

The shooter “had a clean record” behaviorally, Army Secretary John McHugh said. There were “no major misbehaviors that we’re yet aware of,” he said.

Lopez had been prescribed the sedative Ambien, McHugh said.