The Associated Press

PIERRE, S.D. (AP)- The state Supreme Court on Thursday overturned the death sentence of a 29-year-old man who pleaded guilty in the March 2000 torture and murder of an acquaintance.

The court unanimously ruled that Briley Piper of Anchorage, Alaska, did not validly relinquish his right to have a jury, rather than a judge, decide whether he got the death penalty or life in prison without parole for the murder of 19-year-old Chester Allan Poage of Spearfish.

The ruling left Piper's first-degree murder conviction intact and sends the case back to circuit court.

One of Piper's attorneys, Steven Binger of Sioux Falls, said his client will ask for a jury to decide if he should get death or life in prison.

"It's a good development that he will now have judgment passed by 12 people on a jury," Binger said.

The prosecutor in the case, Lawrence County State's Attorney John J. Fitzgerald, said he will continue to seek the death penalty when a jury determines Piper's sentence. "The facts haven't changed, just the passage of time."

Poage's mother, Dottie Poage, did not immediately respond to a request for comment made through Fitzgerald. She has said she doesn't want reporters to contact her directly.

In its decision, the state Supreme Court noted that the judge who sentenced Piper, Circuit Judge Warren G. Johnson of Deadwood, told him that all 12 jurors would have to agree on a sentence if he put his fate in their hands. In fact, Piper would have gotten a mandatory life sentence if even a single juror had decided against death, the court noted.

"Consequently, without an adequate explanation by the judge that one juror could, in effect, choose life, Piper's waiver of a jury trial on the death penalty cannot be considered knowing or voluntary," Justice Judith Meierhenry wrote.

Piper and Elijah Page of Athens, Texas, pleaded guilty to murdering Poage and were sentenced to death. Page ended his appeals and was executed two years ago.

A third man, Darrel Hoadley of Lead, pleaded not guilty and was convicted by a jury, which sentenced him to life in prison.

Prosecutors said the three abducted Poage as part of a scheme to burgle his mother's home when she was on vacation and killed him so there would be no witnesses to their theft of a Chevy Blazer, stereo, television, coin collection, video game and other items.

As Poage begged for his life, the three men made him take off most of his clothes and forced him into an icy creek. They stabbed him repeatedly, kicked him in the head 30 to 40 times and then bashed him with large rocks. Poage also was forced to drink hydrochloric acid. The torture lasted at least two hours.

Poage's body was found several weeks later in the stream.

Poage has appealed his conviction twice. The state Supreme Court upheld his conviction in 2006.