Mr. Baum raised his hand.

In the Bronx, Pierre Sussman, a defense lawyer hunting for evidence of police misconduct, noticed that Detective Scarcella’s name showed up in several troubled cases. He did a computer search, discovered Mr. Ranta’s name and visited him in prison, where he agreed to take on his case.

Soon the last vestiges of evidence fell away. A man who was 13 at the time of the murder, Menachem Lieberman, testified back then that he had seen Mr. Ranta sitting in a car near the murder site.

Now, reached at his home in Montreal, Mr. Lieberman said the case had nagged at him for years. “Before I entered the” lineup room, he told investigators, “a police detective told me to ‘pick the guy with big nose.’ ”

He picked Mr. Ranta, he said, “because he had the biggest nose.”

And Mr. Drikman’s girlfriend, Elizabeth Cruz, also abandoned her story and apologized. “I made up everything,” she said in an affidavit, in hopes of gaining a deal for her boyfriend.

Mr. Drikman also stated that he fabricated his account, and that detectives and Mr. Bloom “framed” Mr. Ranta.

The case against Mr. Ranta had come undone.

“What’s important to me is that this fellow should not be in prison one day longer,” Mr. Hynes said in a telephone interview on Tuesday.

All that remains is for Mr. Ranta, now 58, to feel the shackles taken off his hands and legs and stand before a State Supreme Court judge.