PAUL DAVENPORT

Associated Press

FLORENCE, Ariz. (AP) - An inmate was executed Wednesday after being convicted of murdering two 13-year-old girls in a ghost town where they were raped, strangled and stabbed before being dumped in a partly flooded mine shaft.

Richard Dale Stokley, 60, was put to death at a prison in Florence two decades after he and another man were convicted of murdering Mandy Meyers and Mary Snyder in 1991 in rural Cochise County.

The execution of Stokley was Arizona's 34th since 1992. Daniel Cook was put to death on Aug. 8 in Arizona's most recent execution.

U.S. Supreme Court rulings cleared the way for the lethal injection given to Stokley. On Tuesday, it denied two appeals on his behalf and declined without comment to block his execution.

In his final appeals, Stokley's lawyers said he was entitled to a new hearing on sentencing evidence. They also said his constitutional rights were violated because the other man convicted in the case is free af ter serving 20 years in prison.

Prosecutors said the Arizona Supreme Court adequately considered evidence on possible leniency for Stokley. Prosecutors also defended the disparity in sentences by saying the other man negotiated a plea agreement.

The girls were killed after they left a July 4th holiday weekend community campout in Elfrida, saying they were going to a restroom. They never returned, instead going with Stokley and Randy Brazeal to the nearby ghost town, authorities said.

Acting Cochise County Sheriff Rod Rothrock, who was the lead detective on the case, said in a recent interview that circumstances of how the girls went with the men were never determined.

Stokley, who was 38 when the girls were killed, was convicted of two counts of first-degree murder. He also was convicted of sexual assault against a minor.

Brazeal, who was 19 when the girls were killed, was released from prison July 2, 2011, after serving his full 20-year sentence . While Stokley said both men participated in the slayings, Brazeal denied involvement in the killings. However, he pleaded guilty to second-degree murder, avoiding a trial that the then-county attorney feared could result in an acquittal because DNA evidence was not yet ready.

Stokley has said he thought his life was worth saving, that he knew he had made "grave and irreversible errors" and that he was sorry he "was mixed up in these awful events that brought me to this." He also said he was sorry for the victims and their families.

But he recently declined to ask the state clemency board to recommend that the governor either delay his execution or commute his death sentence in prison. A clemency request would be futile because the board hadn't shown mercy to other death-row inmates, he told the board in a handwritten letter.

"I don't want to put anyone through that, especially since I'm convinced that ... it's pointless," he wrote. "I reckon I know h ow to die, and if it's my time, I'll go without fanfare."

Copyright 2012 The Associated Press.