KILLEEN, Texas - At least three people were still in critical condition Wednesday evening after a troubled Iraq war veteran's shooting spree at Ft. Hood ended with 16 people wounded and four dead, including the shooter, officials said.

Federal officials said Army serviceman Ivan Lopez, 34, was being treated for anxiety, depression and was under evaluation for post-traumatic stress disorder at the time of the shooting on the base. He was armed with a .45-caliber Smith and Wesson semiautomatic pistol that he had purchased recently.

Lopez was married and lived near the base, and late in the afternoon, his wife came out in the courtyard of their apartment building and broke out in tears when she heard her husband identified on the news as the shooter, a neighbor, Xanderia Morris, told the Los Angeles Times.

A group of two adults and three children arrived to keep Lopez's wife company, Morris said; she had been extremely worried about her husband and was concerned that he was one of the victims.

But when she found out her husband was thought to be the shooter, "everybody broke down in tears," Morris said.

Neighbors said the family - including Lopez's wife and their 2-year-old daughter - moved in a few weeks ago, and few people seemed to know them.

"He was always smiling whenever I'd see him," said Morris, a cook. "The wife, she was really nice too, but she didn't speak much English."

When Morris would get up at 4 a.m. each morning to prepare for work, she would see Lopez in an Army-issue T-shirt and shorts leaving for what she assumed was Ft. Hood.

In the initial chaos after the shooting, officials radioed one another that there might have been two suspects; one was "down," but the other was described as a driving a Toyota Camry.

Police had been observing Lopez's apartment complex for a few hours and drew their guns and handcuffed a Los Angeles Times reporter who arrived driving a rented Camry on Wednesday evening, before letting him go.

Lopez's wife left with police in an unmarked car.

At a Wednesday evening news conference with a Ft. Hood entrance as the backdrop, officials said there were no indications that the shooting spree was terrorism-related, but they planned to scour Lopez's record for warning signs.

Authorities later did not provide any indication they were seeking a second suspect.

Lopez served four months in Iraq in 2011, and had not formally been diagnosed with post-traumatic stress disorder; nor was he in the process of leaving or getting kicked out of the Army, Lt. Gen Mark A. Milley told reporters.

However, there were reports that Lopez had self-reported a brain injury after returning from Iraq and that he was on medication, Milley said. He had not been awarded a Purple Heart.

Officials were still trying to determine the exact sequence of events of the shooting, but think it began about 4 p.m. in the 1st Medical Brigade area of the base. Officials think he walked into one of the buildings, began shooting, got into a vehicle, fired from his vehicle, and then headed into another building where he also opened fire.

Within 15 minutes, law enforcement arrived on the scene, and Milley said it was a female military police officer who confronted Lopez in a parking lot.

She was approaching Lopez and was about 20 feet away when he put his hands up, then reached under his jacket, pulled out his pistol, and she "engaged," Milley said. That's when Lopez put his gun to his own head and killed himself, Milley said.

Of the eight victims who were taken to Scott and White Memorial Hospital in Temple, the majority had been shot once, hospital officials said. The victims' injuries ranged from superficial, mild and life-threatening; some were hurt by breaking glass and while trying to escape.

All of the victims were service members, officials said.