PHOENIX -- A man set to be the last person put to death in Arizona using a controversial three-drug lethal injection method has won a reprieve while the U.S. Supreme Court considers an unrelated issue in his case.

The high court on Monday granted a stay of execution for Daniel Wayne Cook, 49, less than 24 hours before he was scheduled to die for killing a man and a teenage boy in 1987 after torturing and raping them for hours.

The execution is now on hold until the Supreme Court makes a decision on an argument by Cook's lawyers that he received ineffective counsel during his post-conviction proceedings.

Cook's attorneys also are fighting the use of the knockout drug sodium thiopental. Similar arguments, however, failed to stop or delay the execution of another Arizona death-row inmate, Eric John King, last week.

The high court's ruling prompted the Arizona Department of Corrections to cancel Cook's execution, which was set for 10 a.m. Tuesday, exactly one week after King lay strapped down in the same room, minutes from taking his last breath.

Cook's death warrant expires Wednesday morning. If the Supreme Court doesn't rule in time, a new warrant must be issued, and that could take weeks.

"We're very happy," defense attorney Robin Konrad told The Associated Press as she drove to a state prison in Florence to deliver the news to Cook. "We hope the U.S. Supreme Court considers this issue seriously."

Ultimately, Konrad is seeking a new sentencing for Cook in hopes that he will get life in prison instead of the death penalty.

Konrad said Cook's attorneys were ineffective during his post-conviction proceedings because they did not present to Judge Steven Conn evidence that Cook endured extreme physical and sexual abuse throughout his childhood.

Cook suffered rape and other abuse at the hands of family members and a group-home worker, according to attorneys and court documents.

He has acknowledged his guilt but has been arguing for a life sentence. He only recently was diagnosed with post-traumatic stress disorder and brain dysfunction stemming from the abuse, and the prosecutor who tried Cook in 1988 has said he would not have sought the death penalty had he known about it.

Assistant Attorney General Kent Cattani said it is Cook's own fault that his trial judge did not know about the abuse because Cook represented himself during his trial and didn't tell the judge about it. He also said Cook's crime is the "worst of the worst" and that if anyone deserves the death penalty, it's him.

"I think eventually when the court considers the petition they will find that Cook has not established a valid basis for relief and that ultimately, the sentence will be carried out," Cattani said.

A clemency board denied Cook's request to recommend that his sentence be reduced to life in prison. And while board members voiced concerns about his abuse, they ruled that the crimes he committed were too severe to merit anything other than the death penalty.

Cook's attorneys also have argued that he shouldn't be executed until the state implements a new single-drug method of lethal injection, a change that Arizona Department of Corrections Director Charles Ryan recently announced because of "perceived concerns" about the current three-drug method. He said the change would begin after King and Cook's executions.

Cook's attorneys say the state broke federal law when it imported sodium thiopental from Great Britain because it was listed in forms as being intended for "animals (food processing)," rather than humans. His lawyers also say the sodium thiopental could be ineffective, leading to severe pain during an execution.

Cattani has denied that Arizona broke the law, and said the paperwork mistake came from a clerical error by the U.S. Food and Drug Administration.

He said the state is switching to one drug because of a U.S. shortage of sodium thiopental, not because of any alleged ineffectiveness.

A three-judge panel with the 9th U.S. Circuit Court of Appeals in San Francisco on Friday upheld a lower court's ruling dismissing Cook's lawsuit over the drug issues, and the full court declined to address the issue over the weekend.

Cook was convicted of two counts of first-degree murder in the July 1987 deaths of Kevin Swaney, 16, and Carlos Cruz-Ramos, 26, in Lake Havasu City, in far western Arizona.

Court documents say Cook and his roommate and co-worker, John Matzke, were drunk and high on methamphetamine when they stole $97 from Cruz-Ramos, who worked with them at a restaurant and had just moved in with them. They then overpowered the Guatemalan immigrant, gagged him and tied him to a chair.

Over the next six hours, Cruz-Ramos was sodomized by Cook, burned with cigarettes, cut and beaten, court documents said. After both men tried to strangle Cruz-Ramos, Matzke said he stood on a pipe over his throat until he died.

Swaney, a runaway and occasional guest at the apartment who also worked at the restaurant, showed up about two hours later.

Cook and Matzke tied him naked to a chair and gagged him, but Matzke said he wouldn't participate in the teen's torture and fell asleep. He awoke to see Swaney crying, and Cook told him he had sodomized the teen and that they had to kill him, court records said.

The two tried to strangle the boy with a sheet. When that failed, Cook strangled him by hand, according to Matzke. They put Swaney's body in the closet on top of Cruz-Ramos'. Court records say Swaney's heart was still beating when he was left for dead.

Cook was arrested after Matzke went to police the next day. Matzke testified against Cook to get a lighter sentence and was released in 2007.