PIERRE, S.D. (AP) — The South Dakota Supreme Court upheld the sentence of the state’s only death row inmate, an Alaska man who pleaded guilty to taking part in a 2000 torture killing.

The justices said the arguments from Briley Piper, 39, of Anchorage, were “untimely” and didn’t contest his guilt, the Rapid City Journal reported. Piper was sentenced to death after pleading guilty in the slaying of Chester Allen Poage, of Spearfish.

Another man who pleaded guilty to taking part in the slaying, Elijah Page, has already been executed. A third man, Darrell Hoadley, was convicted at trial and sentenced to life in prison.

Piper argued in his latest appeal that his guilty pleas were not made voluntarily or intelligently, and he blamed his defense counsel for that.

However, the court said in its ruling Wednesday that Piper had “experienced” attorneys who provided sound advice when they told him that the evidence against him was overwhelming and that jurors would convict him. Piper also thought that taking responsibility could serve as a mitigating factor in his sentencing.

Prosecutors say Piper, Page and Hoadley were high on methamphetamine and LSD when they decided to burglarize Poage’s home on March 12, 2000. After enticing Poage to go to his home, the men pointed a gun at him, forced him to the floor kicked him in the head until he was unconscious, then tied his hands behind his back, prosecutors said. When he awoke, they forced him to drink a mixture of crushed pills, beer and hydrochloric acid, authorities said.

The trio buried Poage naked in the snow but he was able to run away, prosecutors said. Prosecutors said Poage’s attackers then pushed him into a creek, where they kicked him and took turns stabbing him. Poage begged for his life, but his attackers stoned him to death, prosecutors said.

Page was executed in 2007. South Dakota’s last execution was in November.