Also distressing, he said, were violations of the “Brady rule” requiring that exculpatory information be handed over to the defense. Three days before trial, the Red Springs police sought to test a beer can found at the scene for fingerprints of Mr. Artis and L. P. Sinclair, listing both as suspects. The can had two fingerprints, one from the victim, another from neither Mr. McCollum nor Mr. Brown. But mysteriously, tests for the other two men never were performed.

None of that was shared with defense lawyers, Johnson Britt said. Nor was the information that Mr. Sinclair, the informer who said Mr. McCollum had admitted killing the girl, had previously said he did not know anything about the murder, and a lie-detector test indicated he was telling the truth.

Another concern: the Red Springs police insisted for years that they no longer had any physical evidence. But this summer, Innocence Commission officials discovered evidence at the police station that included hair samples from the scene. No DNA from the newly found evidence matched Mr. McCollum’s or Mr. Brown’s.

Kenneth J. Rose, a lawyer for Mr. McCollum and senior staff attorney of the Center for Death Penalty Litigation in Durham, said the confessions that constituted almost the entire case were false. An investigator knowledgeable about the crime scene and the autopsy attended Mr. McCollum’s interrogation, contaminating a session at which investigators fed his client details, Mr. Rose contends.

Taken at face value, he added, the statement from Mr. McCollum purports to show a mentally impaired defendant somehow with precise recall of many crime scene details, including the brand and number of beer cans, and brand of cigarettes smoked by other perpetrators who, the confession states, were also involved. (Two supposed co-conspirators were quickly found to have credible alibis.)

“It’s just astounding that people given so much power over other people’s lives, and who can totally destroy people’s lives, are so unwilling to consider facts,” said Mr. Rose, who intends to petition the governor for an innocence pardon. (At Mr. McCollum’s 1991 retrial, one interrogator testified that details of the confession did not come from the police. Another of the investigators on the case, Kenneth Sealey, now the Robeson County sheriff, did not return a phone call seeking comment.)