Raiford, Florida - A self-confessed serial killer convicted of murdering his wife and another woman was executed by lethal injection in Florida on Thursday.

James Phillip Barnes (61), who did not seek to halt his execution, was put to death at 6:00 PM EDT at Florida State Prison, local media reported.

Barnes was serving a life sentence for the 1997 murder of his wife, Linda, when he confessed to the 1988 rape and murder of Patricia Miller, a 41-year-old nurse.

He was sentenced to death in 2007 for Miller's murder.

Barnes was interviewed by German director Werner Herzog for a 2012 TV show called On Death Row and confessed to two other murders for which he has never faced charges.

In late July, the Florida Conference of Catholic Bishops urged Governor Ron DeSantis to stay Barnes' execution.

"Mr. Barnes' willing acceptance of death... does not absolve the state from bringing it about," they said in a letter. "Simply put, no one should be executed in our modern penal system, even if they willingly accept it."

DeSantis, who is a candidate for the 2024 Republican presidential nomination, signed Barnes' death warrant and declined to stay his execution.

Barnes was the fifth inmate executed in Florida in 2023.

There have been 17 executions in the US this year.