“We have grave doubts and, in fact, do not believe that it was true,” Mr. Hale said.

After the hearing, the Brooklyn district attorney, Ken Thompson, spoke outside the courtroom. “These wrongful convictions represent a systemic failure, a failure by prosecutors, defense attorneys, by judges, by the system,” he said. “These wrongful convictions destroy lives, and no matter what happens, Ms. Gathers will not get back those 10 years.”

Ms. Gathers was convicted of manslaughter in the death of Michael Shaw, 71, who was attacked and robbed inside his apartment in Crown Heights, Brooklyn, in 1991. He died of complications from the assault six months later, in 1992. Ms. Gathers was convicted in 1998, and has been free since she was paroled on March 2, 2007, after serving 10 years in prison.

Ms. Gathers was approached by Mr. Scarcella on the street a month after Mr. Shaw’s death “because she fit the description of one of the assailants,” according to a statement released by the district attorney’s office. She denied being connected to the attack, and pointed to a woman who she believed had done it, but years later, as the investigation continued, she was again interrogated by Mr. Scarcella. In 1997, she confessed — the only evidence presented at trial.

But an examination by Mr. Thompson’s office determined that Ms. Gathers had “made a false confession based, in part, on the defendant’s inability to articulate her role in the assault; perceived inaccuracies in the statement itself; and the lack of details in the statement,” the district attorney’s statement said. Investigators determined that the “complete lack of a coherent narrative in the defendant’s confession, combined with apparent factual errors, amount to reasonable doubt in the validity of the confession itself.”

Among those inconsistencies, Mr. Hale said in court on Tuesday, were statements that the victim had been in a wheelchair. In fact, he had never used one.