Florida Gov. Ron DeSantis, a Republican, signed a death warrant for a man who confessed to the 1988 rape and murder of a nurse in Brevard County.

With DeSantis' signature, 61-year-old James Phillip Barnes is scheduled to be executed on Aug. 3, FOX 13 reported. Barnes was sentenced to death in 2006 after pleading guilty to the violent murder of 41-year-old Patricia "Patsy" Miller.

In a letter to an assistant state attorney in 2005, Barnes admitted that he broke into Miller's condominium in Melbourne and raped her two times before killing her and setting her body on fire. He was convicted of first-degree murder, burglary, two counts of sexual battery with a weapon and arson.

Miller’s death went unsolved for a decade before DNA evidence was matched in 1998 to Barnes, who was already serving a life sentence for the 1997 murder of his wife. He was questioned earlier in Miller's case, but refused to speak with law enforcement, court records revealed.

FLORIDA GOV. DESANTIS SIGNS BILL ALLOWING JURIES TO SENTENCE AN INMATE TO DEATH WITHOUT UNANIMOUS VOTE

James Phillip Barnes mugshot

James Phillip Barnes is scheduled to be executed on Aug. 3 for the violent murder of 41-year-old Patricia "Patsy" Miller. (Florida Department of Corrections)

Barnes' confession letter to the attorney came after he converted to Islam. He told prosecutors he wanted to clear his conscience while fasting during Ramadan, according to Florida Today.

Barnes, who did not know Miller, said he entered her residence through a bedroom window on April 20, 1988, and confronted her with a knife, according to court documents. He raped Miller twice, attempted to strangle her with the belt from her bathrobe and then struck her in the head with a hammer.

In an attempt to conceal the crime, Barnes admitted to using shoelaces to tie Miller to the bed before setting it on fire. A medical examiner determined that she died from blunt-force trauma to the head, FOX 13 reported.

He was reportedly in her home between 45 and 60 minutes.

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Florida Gov. Ron DeSantis

Florida Gov. Ron DeSantis signed a death warrant for a man who confessed to the 1988 rape and murder of a nurse in Brevard County. (CHENEY ORR/AFP via Getty Images)

"She knew he was going to kill her for the duration of her conscious state, and she was unable to resist due to being bound and overpowered by the defendant," then-Brevard County Circuit Judge Lisa Davidson wrote in her 37-page decision to sentence Barnes to death. "Patricia Miller suffered, over a period of time, a terrifying ordeal culminating in a horrifying death at the defendant's hands."

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Barnes "stated unequivocally that he went there to murder Ms. Miller and that it was not an afterthought," the judge wrote, adding that he "worked calmly and coolly toward his goal" of murdering her in a "brutal and ruthless manner."

The August execution will make Barnes the fifth inmate to die by lethal injection in Florida this year.