A man has been convicted of murder in the death of another man almost five decades ago.

Richard Keiper, of Boyd, Texas, was convicted Monday in the October 1968 death of Alfred Barnes, a 40-year-old assistant to the vice president at steel producer Bethlehem Steel.

Hunters found Barnes' bullet-riddled body in a field near Effort, and his car later was recovered in New Jersey.

Prosecutors said Keiper, 68, was arrested in September 2013 after confessing his involvement in Barnes' death. Authorities said he gave two versions of what happened but said in both that he acted in self-defense when Barnes pulled a gun on him.

Defense attorneys cited the lack of DNA evidence or witnesses and the loss of other evidence such as the bullets and shell casings. They argued unsuccessfully for a mistrial Monday morning, citing what they called an improper remark about a prospective prosecution witness.

First Assistant District Attorney Michael Mancuso hailed the work of investigators for the conviction so many decades after the crime.

"To find people who, A, are still alive, B, are able to remember and articulate what had happened, that's no easy task," he said.

Since Keiper will be sentenced under laws in effect at the time, he faces life in prison without the possibility of parole. He'll be sentenced in October.