Arkansas death row inmate Jack Harold Jones Jr., who was executed in 2017 for a 1995 Arkansas murder. (AP Photo/Mike Wintroath, File)

For almost 40 years, no one doubted serial rapist Ronald Stewart murdered Regina Harrison in a South Florida park — not police, not prosecutors and not her family.

He pleaded guilty in Fort Lauderdale to three rapes, was convicted of other attacks in Mississippi and when accused of Harrison's 1983 slaying, he pleaded no contest to second-degree murder. He was sentenced to 50 years in prison, where he died of cancer in 2008, never disputing he killed Harrison, a 20-year-old college student.

But on Thursday, the Broward County state attorney's office asked a judge to throw out Stewart's murder conviction, saying he didn't do it. Her killer, they say, was Jack Jones, a serial murderer executed by Arkansas in 2017 for a woman's 1995 rape and slaying.

Jones confessed to Harrison's killing in a letter to his sister that he told her to open a year after his death. In it, Jones told her to give the letter to the detective who investigated a 1991 Fort Lauderdale murder he confessed to in 2003 — he had told the detective he'd killed a third woman and would eventually tell him who.

The sister forwarded the letter last year and DNA testing confirmed Jones, not Stewart, killed Harrison at a Hollywood, Florida, park. Prosecutors say confessions, identifications and other evidence show Stewart did commit the rapes and that those sentences would not have allowed his release before his death.

“The Broward State Attorney's Office and Hollywood Police Department regret the roles our agencies played in Stewart's conviction,” the agencies said in a statement. “Although Stewart is now deceased, it is appropriate that the record be corrected.” They said Jones' DNA is now being tested against other slayings in Florida and elsewhere.

Richard Harrison, the victim's brother, said Thursday that he and their parents, who are now elderly, were stunned to learn the man they thought killed Regina was innocent of her death. He said Stewart came up for parole in Mississippi but never denied guilt. Harrison, a Tampa attorney who represents municipal governments, said he understands why prosecutors now must correct the record.

“If this did not involve my family personally, this would be a fascinating episode of 'CSI,' ” he said. “ But it doesn't make Stewart any less evil and it certainly doesn't make him any less dead. And Jones has already been executed … and we can only execute people once.”

He said his sister was a kind, deeply religious young woman who was attending Palm Beach Atlantic College, a Christian school in West Palm Beach. He said she hadn't figured out her career but would have taken a job helping others.

“She was a really sweet kid,” he said.

Regina Harrison had gone for a dinnertime bike ride from her parents' home on May 2, 1983, but didn't return. A witness told detectives she had been riding on a popular path that runs along Hollywood Beach with a skinny, long-haired man on a black bike. Her body was found the next day in a nearby park. She had been raped and strangled.

No arrest was made for five months until a Fort Lauderdale detective saw a television story about the killing. He had been part of a task force that had arrested Stewart for a series of rapes — and when captured, the skinny, long-haired man had been riding a black bike. The woman who had seen Harrison at the beach picked Stewart out of a photo lineup. An acquaintance said Stewart had confessed to killing a woman in a park.

Stewart was indicted and the plea deal closing the case finalized. He went to Mississippi to serve his sentence, where he stayed until he was sent to Florida a year before his death.

Jones was arrested in 1995 in Arkansas for the rape and strangulation of a 34-year-old accountant, Mary Phillips, in her office and the beating of her 11-year-old daughter. He was convicted and sentenced to death. In 2003, DNA connected him to the 1991 rape and strangulation at a Fort Lauderdale hotel of Lorraine Barrett, a 32-year-old Pennsylvania tourist. He cooperated, pleaded guilty and was sent back to Arkansas to await execution.

He gave the letter to his sister to hold in about 2007. In it, Jones says he was haunted by Regina's ghost for three years.

“She forgave me. I never forgave myself,” he wrote. He said he wanted the Harrison family to know “I am deeply sorry, that I couldn't rest easy until they knew.”

By his execution, Jones had lost a leg to diabetes and said he was ready to die.

But why he confessed to two murders but not Harrison's until his own death is knowledge he took to the grave.

Terry Spencer reports for the Associated Press.