
Neil Kookoothe: Priest, nurse, lawyer —
When the Rev. Neil Kookoothe discovered a key piece of evidence in the death row murder case against Joe D'Ambrosio, he said his "heart sank into the pit of his stomach." Click through the gallery for case details and crime scene photos.

Death row convict: Joe D'Ambrosio —
A three-judge panel in Cleveland convicted D'Ambrosio on charges of murder, kidnapping and burglary in the stabbing death of Anthony Klann. D'Ambrosio was sentenced to death.

The victim: Anthony Klann —
Nineteen-year-old Anthony Klann, right, suffered from a learning disability, said his father, Richard Klann, center. When he learned of his son's death, Richard Klann said, "it was the coldest day of my life."

Prosecution witness: Eddie Espinoza —
During D'Ambrosio's trial, a co-worker named Eddie Espinoza offered his version of what happened the night Klann was killed.

The pickup truck —
Espinoza testified that he, D'Ambrosio and a man named Michael Keenan forced Klann into their pickup truck the night of September 23, 1988. Espinoza testified that they ordered Klann to help them find a man named Paul "Stoney' Lewis who had allegedly stolen drugs from them. According to court documents, Espinoza testified the trio grew frustrated with Klann when they failed to track Lewis down.

Michael Keenan —
According to his statement to police, Espinoza said Keenan cut Klann's "throat with a big knife" and threw him into Cleveland's Doan Creek. Keenan then handed the knife to D'Ambrosio and said "finish the job," according to Espinoza's statement. Espinoza told police he then heard Klann scream, "Please don't kill me." Espinoza said, "Joe didn't stop. I heard him in the water. I never saw Anthony after that," according to the statement.

Crime scene: Doan Creek —
Ernest Hayes was among the first police homicide detectives at the crime scene, according to his affidavit. "There was no evidence of a struggle in or around any of the surrounding area where Anthony Klann's body was found," Hayes' affidavit said.

Crime scene: Doan Creek —
According to the affidavit, it was Hayes' opinion that "... Anthony Klann was not murdered at Doan Creek, but he was murdered elsewhere and his body was dumped at Doan Creek." The prosecution didn't disclose this information during the trial, according to the U.S. Court of Appeals. Hayes' statement directly disputed Espinoza, who said D'Ambrosio killed Klann in the creek.

Arrested —
Police arrested D'Ambrosio at his apartment. He told CNN's "Death Row Stories" he had no alibi and was alone and asleep at the time of the murder. D'Ambrosio said he had been honorably discharged from the Army a few years earlier, and had no criminal record.

Evidence: Bloody bandage —
This police crime scene photo shows a blood-soaked bandage found in D'Ambrosio's apartment.

Evidence: Blood trail —
Several trails of blood, seen in this police crime scene photo, were found in the apartment hallway.

Evidence: Knife on sink —
This police crime scene photo shows one of several Bowie knives recovered from D'Ambrosio's apartment.

Evidence: Two additional knives —
Cuyahoga County Coroner Elizabeth Balraj stated in court documents that all Klann's "knife wounds could have been caused by" a knife that police said was found in D'Ambrosio's apartment. However, she also said "it was possible that another knife could have been involved in the murder."

Kookoothe's two discoveries —
Kookoothe, a Roman Catholic priest who also is a trained nurse and attorney, agreed to look into D'Ambrosio's case. Kookoothe said the severe neck wound Klann suffered would have made it impossible for Klann to have spoken the words "please don't kill me," as Espinoza told police. Next, Kookoothe remembered that a reporter named Martin Kuz had told him Klann had been subpoenaed to testify at a rape trial. Kookoothe's research found that the man whose trial Klann was subpoenaed for was none other than Paul "Stoney" Lewis.

Paul 'Stoney' Lewis —
A man named Christopher Longenecker testified in 2004 that Lewis, shown here, raped Longenecker shortly before Klann's murder. Immediately after the alleged rape, Klann walked in on the two men -- which gave Longenecker a chance to escape, Longenecker testified. Longenecker said Klann knew he was upset. Longenecker told Klann that "something had just happened," and Longenecker suspected Klann understood what that meant, according to the testimony.

Paul 'Stoney' Lewis —
Later, Longenecker, according to court documents, was subpoenaed to testify against Lewis, shown here. But Longenecker misread the subpoena and missed the trial date. As a result, the rape indictment against Lewis was dismissed. If Longenecker's story had been introduced as evidence in D'Ambrosio's trial, it "would have ... increased a reasonable juror's doubt of D'Ambrosio's guilt," a federal court wrote.

The prosecutor —
"I didn't see any connection" between the rape case and D'Ambrosio's case, trial prosecutor Carmen Marino told CNN's "Death Row Stories." It's unlikely "someone would murder another witness to keep them from testifying."

Free after two decades: Joe D'Ambrosio —
The undisclosed conclusions about the crime scene and about Klann's role in the rape case were enough to overturn D'Ambrosio's conviction. Before the state could retry him, Espinoza died. Without his testimony, Judge Joan Synenberg dismissed all charges against D'Ambrosio. The state's appeal went to the U.S. Supreme Court, which in 2012 refused to consider the case. Finally, after more than 20 years on death row, D'Ambrosio could move on as a free man. He has a civil lawsuit pending against the state of Ohio, Kookoothe said, which D'Ambrosio hopes will yield compensation for his ordeal.