Mr. Gardner’s lawyer, Andrew Parnes, said he would make a new appeal to the State Supreme Court, which previously upheld the death sentence, arguing that his client did not receive proper help with experts and research before his sentencing and that execution after such a long wait would be cruel and unusual punishment.

Image Ronnie Lee Gardner, center, with his defense team at the Matheson Courthouse in Salt Lake City on Friday. Credit... Pool photo by Francisco Kjolseth

Mr. Gardner also has the right within the next seven days to ask the Board of Pardons to commute his sentence to life in prison.

For decades, Utah let condemned prisoners choose whether to die by hanging or the firing squad, then more recently between lethal injection and a firing squad. In 2004, the Legislature ended the practice, making lethal injections standard. But to avoid legal complications, the state has allowed pre-existing prisoners who had selected the firing squad to remain with that option if they want.

Mr. Gardner picked the firing squad at the time of his initial death sentence in 1985. In two later court appearances he seemed to have had a change of heart, switching his choice to lethal injection. But in 1996 — the same year that the last prisoner in Utah, and the country, was executed with bullets — he said he had switched only out of concern for his children, who were then young, and that he had always preferred death by gunfire.

“I like the firing squad,” he told The Deseret News at the time. “It’s so much easier ... and there’s no mistakes.” In a telephone interview Friday, Mr. Parnes said that he would not comment on Mr. Gardner’s reasons for “his personal decision.”