A man shot in the back 35 years ago has died of complications from the shooting and his death has been ruled a homicide — but prosecutors fear the trail for the suspect has long ago gone cold.

So far, police and prosecutors said they have been unable to find out who shot Craig Buford in the back in Denver in 1973. It was a time before records could be filed on computers.

Lynn Kimbrough, a spokeswoman with the Denver District Attorney's Office, told The Associated Press on Tuesday that her office might file charges if evidence and witnesses can be found.

"After 35 years has passed, that might be a pretty tall order," Kimbrough said.

Although hospitalized for several months after the shooting, Buford healed and had few lasting effects, his relatives said. He drove city buses in Denver and Seattle and was a truck driver before retiring. He moved to Fort Worth about a year ago.

Buford, 54, was hospitalized recently and had surgery after doctors determined his colon had ruptured; he died Dec. 29. The Tarrant County Medical Examiner's Office ruled Buford's death a homicide, caused by multiple organ failure from complications from his wound.

"He never had any serious health problems, so I was a little surprised to hear all this homicide business after all these years," his wife, Carolyn Buford, told the Fort Worth Star-Telegram in Tuesday editions.

She said her husband told her about the shooting but she didn't know him then. She said he had gone to school to pick up a girlfriend and started gambling with other teens. She said he won some money, and when he refused to give in to the other teens' demands to return it, he was shot.

According to a Denver newspaper article, Craig Buford drove himself to the hospital and named a 17-year-old as the shooter.

Craig Buford didn't dwell on the shooting, his wife said. "He ran into the guy one time, and he said the guy was kind of scared about seeing him," Carolyn Buford told the Fort Worth newspaper. "He told him, 'Just forget about it. It's over with."'