Thomas Alton Caffall III, 35, who was killed by a responding police officer, was having "difficulties" with his mental health in recent years, his mother, Linda Weaver, told The Huffington Post.
Caffall's stepfather, Richard Weaver, told KPRC-TV, Houston, Caffall was "crazy as hell."
"At one point, we were afraid that he was going to come up here and do something to his mother and me," he told the TV station, adding Caffall was a "ticking time bomb" who quit his job nine months ago and vowed never to work again.
"We are just devastated," Linda Weaver told the Post. "He's been very deeply troubled."
She added she was horrified at the loss of life.
"If you're going to commit suicide, why take all these other people with you?" she said.
Caffall was being served an eviction notice when he opened fire, police said.
The tenant was armed when he met Constable Brian Bachmann outside Caffall's small, one-story house about 2 blocks from the Texas A&M campus, police said.
Serving the early-afternoon eviction notice turned into a half-hour shootout Monday that left three people dead, including Bachmann and Caffall, who died after he was taken into custody.
The hail of bullets also killed bystander Christopher Northcliffe, 51, of College Station, Texas, where Texas A&M is located.
College Station police officer Justin Oehlke was shot in the calf. Two of his colleagues, officers Brad Smith and Phil Dorsett, were treated and released, the Houston Chronicle reported.
Houston mother Barbara Holdsworth was seriously injured when bullets hit her vehicle, officials said. She underwent surgery but remained in serious condition early Tuesday.
She was in College Station helping her daughter, an A&M student, move, the Chronicle said.
Neighbor Rigo Cisneros, 40, an Army medic who served a tour in Afghanistan, heard the shots and videotaped the shooting from his home across the street.
"It was a stupid thing to happen. An eviction notice. What possibly could you be thinking? It's so pointless," he told the Chronicle, adding he didn't know his neighbor.
His video shows officers storming toward the house with guns drawn, repeatedly yelling "do not move" to Caffall. Police were met with gunshots and fired their weapons.
Caffall did not have an extensive criminal history, court records indicated.
He was arrested in 2006 for driving with an invalid license and pleaded no contest to a lesser charge.
His Facebook posts reveal a man fascinated by firearms, including one he called "my new toy" last year, the Chronicle said.
Presumptive Republican presidential nominee Mitt Romney commented on the shooting saying "thoughtful consideration" should be given to end gun violence.
"This is not a matter of the weapon that's used," Romney told reporters in Miami. "It's the matter of individuals and the choices they make. ... I don't think gun laws are the answer."
President Barack Obama was not believed to have immediately commented on the shooting.
Obama and Romney agreed that new gun legislation was not needed after the shooting rampage at a Colorado movie theater.