An 83-year-old Nevada prison inmate serving two life terms, including one for killing a fellow prisoner, has died three decades after his case resulted in a U.S. Supreme Court decision that spared him the death penalty.

Raymond Wallace Shuman died at Carson Tahoe Medical Center in Carson City on Friday, nearly 60 years after he was committed to his first sentence for murder in Nevada's Mineral County in 1958.

The state Department of Corrections did not release a cause of death, but said he previously had been housed at the Northern Nevada Correctional Center in Carson City before being admitted to the hospital. An autopsy will be conducted, the department said.

Department spokeswoman Brooke Santina said Saturday she didn't know whether Shuman was the longest-incarcerated Nevada inmate but that she thought there may be at least one older inmate in the prison system.

Shuman's second life sentence was the result of the 1973 killing of fellow prisoner Ruben Bejarno in an adjoining cell in the since-closed Nevada State Prison. Bejarno was set on fire when two cans of lighter fluid were thrown into his cell.

Shuman was sentenced to death automatically in the Bejarno killing under a since-repealed Nevada law that required capital punishment for a prisoner convicted of first-degree murder while already serving a life sentence.

The Nevada Supreme Court upheld Shuman's conviction and death sentence in the prison killing, but the U.S. Supreme Court overturned the death sentence in 1987 while upholding his conviction.

The U.S. Supreme Court had previously declared mandatory death penalty laws unconstitutional, saying defendants were entitled to present possible mitigating evidence.

However, until Shuman's case, "the court had specifically and explicitly reserved judgment on the issue of a mandatory death sentence imposed on a prisoner already serving a life sentence," Michael W. Bowers, a political science professor at the University of Nevada, Las Vegas, wrote in a Western State Law Review article.

The court's Shuman decision "continued its longstanding practice of not permitting the mandatory imposition of the death penalty," Bowers wrote.

Bejarno died three days after being burned. He twice said at the hospital that Shuman set him afire.

A Nevada Supreme Court ruling said Shuman's fingerprints were on the cans, that he also suffered burns and was seen making throwing motions as Bejarno ran from his cell in flames. The two reportedly had been fighting just before the incident over opening a window near their cells.