LUCASVILLE, Ohio (AP) — An Ohio inmate condemned to die appeared to gasp several times during his prolonged execution Thursday with the first use of a lethal injection process never before tried in the U.S.

Death row inmate Dennis McGuire made several loud snorting or snoring sounds during the more than 15 minutes it appeared to take him to die. It was one of the longest executions since Ohio resumed capital punishment in 1999.

Ohio officials used intravenous doses of two drugs, the sedative midazolam and the painkiller hydromorphone, to put McGuire to death. The method has been part of Ohio's execution process since 2009, though was never used.

McGuire's adult children sobbed a few feet away in a witness room as they watched him die at the state death house in Lucasville in southern Ohio.

"I'm going to heaven, I'll see you there when you come," McGuire said. He opened and shut his left hand several times before the drugs took effect, appearing to wave to his children.

McGuire's attorneys argued he would experience "agony and terror" as he struggled to breathe, while state attorneys disputed that scenario. A federal judge sided with the state but acknowledged the new method was an experiment. At the request of McGuire's lawyers, Judge Gregory Frost ordered the state to photograph and then preserve the drugs' packaging boxes and vials and the syringes used in the execution.

McGuire, 53, was sentenced to death for the 1989 rape and fatal stabbing of Joy Stewart in Preble County in western Ohio. The newly married Stewart was eight months pregnant at the time.

Stewart's slaying went unsolved for 10 months until McGuire, jailed on an unrelated assault and hoping to improve his legal situation, told investigators he had information about the woman's Feb. 12, 1989, death. His attempts to blame the crime on his brother-in-law quickly unraveled and soon he was accused of being the Joy Stewart's killer, according to prosecutors.

More than a decade later, DNA evidence confirmed McGuire's guilt, and he acknowledged that he was responsible in a letter to Gov. John Kasich last month.

"One can scarcely conceive of a sequence of crimes more shocking to the conscience or to moral sensibilities than the senseless kidnapping and rape of a young, pregnant woman followed by her murder," Preble County prosecutors said in a filing with the state parole board last month.

His attorneys argued McGuire was mentally, physically and sexually abused as a child and has impaired brain function that makes him prone to act impulsively.

"Dennis was at risk from the moment he was born," the lawyers said in a parole board filing. "The lack of proper nutrition, chaotic home environment, abuse, lack of positive supervision and lack of positive role models all affected Dennis' brain development."

Documents obtained by The Associated Press show McGuire unsuccessfully sought a reprieve in recent weeks to try to become an organ donor. In November, Kasich granted a death row inmate an eight-month reprieve to let the prison system study his request to donate a kidney to his sister and his heart to his mother.

Kasich said McGuire couldn't identify a family member who would receive his organs, as required under prison policy.

___

Andrew Welsh-Huggins can be reached on Twitter at https://twitter.com/awhcolumbus