As James Dailey’s appeals slowly advanced through the courts, his attorneys at the Capital Collateral Regional Counsel — a state agency that represents indigent death-row inmates — argued that the state had, by putting Skalnik on the stand, used false testimony to convict him. To prove it, they pointed to the claims Skalnik himself made in 1988, when he accused prosecutors of knowing that the confessions he recounted were highly suspect and of concealing from juries the rewards he was given for his testimony. But the courts were indifferent. In a 2007 opinion, the Florida Supreme Court noted that Skalnik’s claims of prosecutorial misconduct had never been substantiated. “Skalnik disavowed the accusations,” read the opinion, and “unequivocally stated that they were false.” The court also accepted the government’s assurances that prosecutors had not engaged in wrongdoing. “The prosecutor in Dailey’s case also testified that she believed Skalnik’s testimony to be truthful at the time of trial,” its justices wrote in their opinion. And with that, any hope of challenging the veracity of Skalnik’s testimony effectively came to an end.

Eight years later, in 2015, the Florida Commission on Offender Review declined to recommend Dailey’s case for a clemency hearing. By then, Dailey and another man, J.D. Walton, were the only people Skalnik testified against who remained on death row. Dailey’s prospects looked grim; after several rounds of appeals, the inexorable fact of his execution loomed.

The following year, a new attorney at the C.C.R.C., Chelsea Shirley, started digging into his case. Shirley, who was less than three years out of law school, brought fresh eyes and indefatigable energy to the decades-long case file and the effort to win Dailey a new trial. At 27, she was younger than the case itself.

As Shirley read the numerous accounts that Dailey’s co-defendant, Jack Pearcy, had given about the night of the crime, she saw nothing to suggest that her client had actually taken part in the murder. “Through the years, Pearcy suggested — but never explicitly said — that he committed this crime by himself,” Shirley told me. She was particularly struck by a sworn statement he made to Dailey’s attorneys in 1993. In it, Pearcy divulged that he had been alone with Boggio in the early-morning hours of May 6, 1985, making him the last known person to see her alive; he did not say what happened to Boggio, only that he returned home alone. “I went in, got Jim up,” Pearcy said of Dailey. “I told him, ‘Come on, let’s go smoke a couple joints, drink a beer or something.’ ” He and Dailey then drove to a nearby causeway, he said, and began tossing a Frisbee around. “He ended up going out in the water,” Pearcy said, “while we was playing Frisbee. We drank beer, we smoked a couple of joints.” His account provided an explanation for why Dailey’s jeans were wet when the two men returned home. It was the same story Dailey had told his attorneys before his own trial — a story they warned him sounded too far-fetched to repeat to a jury.

On April 20, 2017, Shirley drove to Sumter Correctional Institution in Bushnell, Fla., an hour north of Tampa, to see Pearcy. She was still in the early stages of her investigation; she did not yet know that she would interview two men who had been incarcerated with Pearcy at different times, who would tell her that Pearcy told them Dailey had nothing to do with the murder. Shirley went to see Pearcy only with the hope that he might be ready, after 30 years, to talk.

Pearcy, a compact, muscular man with penetrating blue eyes, did not seem surprised that she had come to visit him, and he agreed to meet with her. She began by reviewing several previous accounts he had given of the hours surrounding Boggio’s murder, in which he suggested that Dailey was at home when he and the teenager headed out into the night. Pearcy listened and nodded along. Finally he asked if he could look at a document she had placed on the table between them; it was an affidavit she had prepared that summarized his previous statements, but it concluded with a declaration that went one step further. “James Dailey was not present when Shelly Boggio was killed,” it read. “I alone am responsible for Shelly Boggio’s death.”

Pearcy read the affidavit line by line, and when he finally spoke, his voice was devoid of emotion. “If you can give me a pen, I’ll sign it,” he told Shirley. He said that he would be willing to testify in court to attest to the accuracy of the affidavit; he just wanted to tell his mother first, he said, to prepare her. It was an astounding admission — and it was enough, Shirley hoped, to win her client a new trial.