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A man who strangled his prison cellmate and made good on a vow to continue killing if he wasn't executed was put to death Wednesday in Virginia's electric chair.

Robert Gleason Jr., 42, was pronounced dead by authorities at 9:08 p.m. at Greensville Correctional Center. He became the first inmate executed in the United States this year and the first to choose death by electrocution since 2010. In Virginia and nine other states, death row inmates are allowed to choose between electrocution and lethal injection.

The Richmond Times-Dispatch reported that one of Gleason’s final words were: “Put me on the highway going to Jackson and call my Irish buddies… God bless.”

Gleason, surrounded by prison officials, was led into the chamber at 8:55 p.m. He smiled and winked toward his spiritual advisor while he was strapped into the wooden chair that would soon be pumping 1,800 volts at 7.5 amps into his body, the report said.

Then, after a metal helmet was placed on his head and a clamp on his right calf, his face was covered with a leather strap with a triangle cut out for the nose. He made a thumbs-up with his right hand for several seconds. His body tensed as he was given two 90-second cycles of electric current before being pronounced dead.

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The paper reported that his body tightened and his skin turned pink. After the second cycle, a physician, as the paper reported, "put a stethoscope to Gleason’s chest just below a tattooed skull and failed to detect a heartbeat."

Gleason was serving life in prison for the 2007 fatal shooting of a man when he became frustrated with prison officials because they wouldn't move out his new, mentally disturbed cellmate. Gleason hogtied, beat and strangled 63-year-old Harvey Watson Jr. in May 2009 and remained with the inmate's body for more than 15 hours before the crime was discovered.

"Someone needs to stop it," he told The Associated Press after Watson's death. "The only way to stop me is put me on death row.”

While awaiting sentencing at a highly secure prison for the state's most dangerous inmates, Gleason strangled 26-year-old Aaron Cooper through wire fencing that separated their individual cages in a recreation yard in July 2010. As officers tried to resuscitate Cooper -- video surveillance shows had been choked on and off for nearly an hour -- Gleason told them "you're going to have to pump a lot harder than that."

Gleason subsequently told AP in phone interviews that he deserved to die for what he did.

"The death part don't bother me. This has been a long time coming," he said in one of the many interviews from death row. "It's called karma."

Gleason said he only requested death in order to keep a promise to a loved one that he wouldn't kill again. He said doing so would allow him to teach his children, including two young sons, what could happen if they followed in his footsteps.

"I wasn't there as a father and I'm hoping that I can do one last good thing," he said previously. "Hopefully, this is a good thing."

Gleason had fought last-minute attempts by former attorneys to block the scheduled execution.

The lawyers had argued that he was not competent to waive his appeals and that more than a year spent in solitary confinement on death row had exacerbated his condition. Two mental health evaluations done before Gleason was sentenced in 2011 said he was depressed and impulsive but competent to make decisions in his case.

Late Wednesday, the U.S. Supreme Court rejected a request for a stay.

Use of the electric chair remains rare in Virginia. Since inmates were given the option in 1995, only six of the 85 inmates executed since then have chosen electrocution over lethal injection.

Cooper's mother, Kim Strickland, had made plans to witness the execution. She has sued the prison system over her son's death and said she hopes Gleason's family can have closure.

"May God have mercy on his soul," Strickland told AP before the execution. "I've been praying and will continue to pray that his family can heal from this ordeal."

Waton's sister, Barbara McLeod, said she had "mixed feelings" about the execution but "didn't want him to be able to kill more people."

"I deeply regret that the Virginia prison system set up my brother to be eliminated without due process as punishment for his mental illness," McLeod said in an email. She, nor anyone else from Watson's family, witnessed the execution.

Gleason did not visit with family before his execution. Inmate's families are not allowed to witness executions in Virginia.

Some protested outside the prison on Wednesday, saying Gleason's threats to continue killing should not be a reason to justify execution.

Despite Gleason's crimes and his insistence on being executed, "the state should not kill its own citizens under any circumstances," said Virginians For Alternatives to the Death Penalty Executive Director Stephen Northup.

Northup said Corrections officials should be able to keep the truly dangerous inmates like Gleason in solitary confinement away from all others: "We have the ability to keep everyone else safe from truly dangerous people without killing them."

Click for more from the Richmond Times-Disptach

The Associated Press contributed to this report