Decades ago, two witnesses linked Curtis Crosland to the killing of South Philadelphia grocery store owner Il Man Heo during a nighttime robbery.

No physical evidence connected Crosland to the scene, according to court documents. He was convicted and sentenced to life in prison based entirely on the witnesses’ statements, the Philadelphia District Attorney’s Office said.

Crosland spent 34 years — more than half his life — in prison for the crime. But the state said investigators may not have handed over “troubling” information that would have undermined the witnesses’ credibility decades ago — and pointed to another suspect.

The case that left Crosland behind bars for decades was recently unraveled by the district attorney’s office. After the office’s conviction integrity unit (CIU) — created to examine assertions of innocence and wrongful conviction — launched an investigation into the case, the 60-year-old was exonerated and released from prison in late June.

Crosland’s legal team at Philadelphia’s Federal Community Defender Office laid the groundwork for the exoneration, federal defender Arianna Freeman said in an email. Led by attorney Claudia Flores, the team investigated Crosland’s case for months, discovered evidence that had been overlooked for decades and presented the case to the CIU.

“I feel exceedingly joyful, happy, that finally, you know … after 30 or more years, after constantly knocking on the door for somebody to please hear me, that day finally came,” Crosland told CNN.

The saga that landed Crosland in prison also began with a door knock.

Police rapped on his door in 1987, he told CNN, three years after the robbery during which Heo was fatally shot. The case had languished, unsolved.

“I remember telling my wife and son, ‘I’ll be back,’ because I didn’t do anything,” Crosland said.

But he didn’t come back. The then-23-year-old went to trial and was convicted of second-degree murder and two lesser charges. Those convictions were overturned, and he went to trial for a second time in 1991. He was convicted again.

After decades of Crosland trying to prove his innocence, the CIU in 2020 launched an investigation into his case.

Assistant District Attorney Patricia Cummings, head of the CIU, told The Washington Post that Crosland’s case had a telltale sign of a wrongful conviction: It was weak from the beginning.

Cases like his often start with inadequate investigation from the police department, she said, and snowball from there.

The investigation unearthed many relevant documents that Crosland’s defense was not privy to, the CIU said, and found the prosecution’s nondisclosure of critical information violated Crosland’s constitutional rights.

Both key prosecution witnesses from Crosland’s trial had been unreliable for decades, the investigation found. During the second trial, one retracted his initial assertion that Crosland had admitted to killing Heo, court documents show. The other admitted in 1988 to falsely accusing Crosland’s cousin of murder in a separate case.

During the grand jury proceedings in which the woman testified against Crosland’s cousin, she mentioned overhearing Crosland talking about Heo’s killing and said Crosland was “afraid someone would tell because there was a reward out.”

A few weeks later, she recanted her testimony from the day. The defense in Crosland’s case was provided a seven-page transcript of what she told the grand jury, the CIU said, but the documents did not explain that she had withdrawn that testimony.

Unknown to Crosland’s defense, the state had planned to prosecute her for false reporting.

Within about a year of Crosland’s initial conviction, according to the CIU, both key witnesses had withdrawn their testimony about his involvement in Heo’s killing. It’s unclear why this information wasn’t given to the defense.

Cummings said there has long been a lack of understanding of what the prosecution needs to pass on to the defense and what investigators need to give the prosecution.

“Oftentimes the information is not passed, and it calls into question the validity of the conviction,” she said.

In affidavits from 2019 and 2020, both witnesses again said they gave false testimony implicating Crosland, the CIU said. One witness said she had been coerced by the police; the other said he was facing a parole violation and hoping the testimony could help him avoid jail.

The CIU said its investigation also pointed to the first man the police had looked into as a more likely suspect. Crosland’s defense was unaware of other suspects during his trials.

Crosland told the Philadelphia Inquirer he was “emotional” when he found out about the information that was not given to his defense.

“It was mind-blowing that all that could be hidden, to convict an innocent man,” he said. “It was painful. It was difficult to even share with my family some of the things I learned that happened to me.”

U.S. District Judge Anita B. Brody of the Eastern District of Pennsylvania ordered Crosland’s release or retrial in late June, and the district attorney dropped the charges the man was convicted of in 1991.

“The responsibility of doing justice does not disappear once a conviction is achieved,” Brody wrote. “In some circumstances, the duty to seek truth can and should extend to cases long closed.”

She echoed the CIU’s message that the state acknowledges Crosland “may very well be actually innocent.”

Including Crosland’s, the CIU said it has supported 22 exonerations since its creation in 2018.

The son of Heo, the man who was killed in the robbery, commended the office for its work.

“My hope is that there are many like you out there. Compassionate, respectful, understanding, competent, professional and genuine,” Charles Heo said in a report from the organization. “ ‘Flip every rock and stone.’ Make us proud of the Justice System by always questioning its integrity with respect to equity. I am deeply thankful for your hard work and continuing to do what is right.”

Crosland’s son Risheen told the Philadelphia Inquirer that he learned at age 16 that his father would “always belong to the state of Pennsylvania.”

“I tried everything I could to get my father out,” he said. “Then when nothing else worked, it seemed like God just showed me what he could really do.”

Read more: