JARRATT, Va. - A man who strangled his prison cellmate and made good on a vow to continue killing if he wasn't executed has been put to death in Virginia's electric chair.

Robert Gleason Jr. was pronounced dead by authorities at 9:08 p.m. Wednesday at the Greensville Correctional Center.

The 42-year-old inmate was the first executed in the U.S. this year and the first to choose to die by electrocution since 2010. In Virginia and nine other states, inmates can choose between electrocution and lethal injection.

Gleason had fought last-minute attempts by former attorneys to stop the execution. He told The Associated Press he deserved to die for what he did.

Gleason was serving life in prison for a 2007 murder when he killed his cellmate in 2009. He strangled another inmate in 2010.