The US state of Virginia has used the electric chair to put to death a man who killed two fellow prisoners to speed up his own execution.
Robert Gleason, 42, was the first Virginia inmate to choose electrocution over lethal injection since March 2010.
The former tattoo artist pleaded guilty to a 2007 murder and subsequently killed two fellow prisoners, while waiving all his rights to an appeal.
Virginia's governor declined to intervene in the case.
Authorities pronounced Gleason dead at 21:08 on Wednesday (02:08 GMT on Thursday) at the Greensville Correctional Center in the town of Jarratt.'Urine-soaked sponge'
Gleason's lawyers had argued he had a long history of mental illness and his condition had deteriorated during a year in solitary confinement.
Two other evaluations deemed him capable of making his own decisions.
He strangled his cellmate, 63-year-old Harvey Watson, in 2009, after tricking him into allowing his hands to be tied by pretending it was part of an escape plot.
According to court records, Gleason taunted his victim by stuffing a urine-soaked sponge into his mouth before killing him.
While awaiting sentencing, he strangled 26-year-old Aaron Cooper.
Gleason said that he asked Cooper to try on a "religious necklace" through a wire fencing separating them.
He had said in multiple interviews that he had waived the appeals process because he knew he would kill again if he was not executed.
"Someone needs to stop it," he told the Associated Press at the time of the first inmate murder. "The only way to stop me is put me on death row."
He repeated threats to murder again in court on numerous occasions.
Governor Bob McDonnell said in a statement on Friday: "Gleason has expressed no remorse for these horrific murders.
"He has been found competent by the appropriate courts to make all of these decisions."
Only 157 death-row electrocutions have taken place out of 1,320 executions since the US death penalty was reinstated in 1976, according to the Death Penalty Information Center.