A Texas man is facing manslaughter charges for reportedly fatally sucker punching an Air Force veteran over a slice of pizza, as reported by the Austin American-Statesman.

Nathan Marshall, 28, (pictured left) is said to have admitted to assaulting Marques Johnson, 33, (pictured right) at 2 a.m. on September 17 near the Driskill Hotel. Johnson, who was knocked unconscious by the blow, died from his injuries the following day.

Authorities say Johnson was out with his wife (also pictured) to celebrate a friend’s birthday when the fatal attack occurred. His preliminary cause of death was blunt force trauma, according to KHOU.

Marshall was identified as the prime suspect after the Austin Police Department released surveillance footage from the assault. The case against Marshall became more damning after officers received another video that showed the 28-year-old walking away from Johnson’s lifeless body, police have stated.

One witness told officers that Johnson had “bumped into someone,” who was later identified as Marshall. A second onlooker claimed an unknown individual hurled a slice of pizza at Johnson, leading him to turn around and ask who threw it. The second witness, who also identified Marshall as the attacker, said Johnson was then punched and fell to the ground.

The Statesman reports that Marshall was taken into custody Thursday on an unrelated charge.

Police are currently looking for a second man who they believe was with Marshall on the night in question, it has been noted.

The suspect’s brother, Kenneth Williams, told KXAN that Nathan has been plagued with mental health issues for years.

“My knowledge—he was diagnosed with some type of schizophrenic state of mind. I don’t feel like he really understands the magnitude of what happened because of his mental state,” he said.

“He’s not no killer like how people are portraying him to be. He just so happened to get into a situation where his mental stability caused him to be in the situation that he is in right now.”

Documents obtained by KXAN indicate that Nathan has two prior assault convictions, among others. He was charged in 2016 with harassment of a public official but the case is pending due to questions surrounding his mental competency.

Nathan is currently jailed on $150,000 bail.

[Featured Image: Austin Police Department/Facebook]