HOUSTON (AP) – A man on death row for 35 years for a Houston robbery where three people were shot and killed and a fourth was severely wounded has died of natural causes, Texas prison officials said Monday.

Max Soffar, 60, died Sunday at the infirmary at the Polunsky Unit prison near Livingston, home of the state’s death row for men, Texas Department of Criminal Justice spokesman Jason Clark said.

Two years ago, Soffar said he had liver cancer and expected to die soon. He and his lawyers long maintained he was innocent, although he was tried, convicted and condemned twice, most recently in 2006.

Only six of the some 250 inmates now on Texas’ death row served more time there.

Soffar’s first conviction was thrown out in 2004 by a federal appeals court panel that agreed with arguments he had deficient legal help at his first trial in 1981. At his second trial, attorneys unsuccessfully argued that a convicted serial killer in Tennessee was responsible for the 1980 fatal shootings.

Jurors decided he should be executed for killing Arden Alane Felsher, 17, who prosecutors said was fatally shot as Soffar was robbing Stephen Allen Sims, 25, an assistant manager at the Fair Lanes Windfern Bowling Center in Houston. Sims and Felsher’s boyfriend, Tommy Lee Temple, 17, also were killed in the attack.

A fourth victim, Gregory George Garner, was shot in the head but lost his left eye and underwent several surgeries. According to Garner, all four were told to lie face down on the floor and then were shot in the head.

Soffar, then 24, was arrested more than three weeks later.

In an August 2014 interview, he told The Associated Press he was a “mentally ill drug addict” at the time and contended police manipulated him into false confessions.

“They ran with it, and here I sit 35 years later,” he said.