SYCAMORE, Ill. – For most of five decades, it seemed no one would ever be held accountable for the murder of a 7-year-old Illinois girl snatched off a small-town street corner as she played.

Now someone has.

Fifty-five years after Maria Ridulph vanished, her friends and family let out a deafening cheer Friday as a judge pronounced a former neighborhood teen — now a 72-year-old man — guilty of the kidnapping and murder. It was one of the oldest unsolved crimes in the U.S. to make it to trial.

The roar of approval soon gave way to loud sobs from those who knew the little girl whose body was found after a five-month search that drew national media attention and haunted people across the country. Jack McCullough, who was 17-year-old John Tessier at the time, showed no hint of emotion.

“A weight has been lifted off my shoulders,” said Kathy Chapman, 63, who was playing with Maria in the snow on the night of Dec. 3, 1957, before she vanished. “Maria finally has the justice she deserves.”

McCullough won Maria’s trust by talking about dolls and giving her piggyback rides, Chapman testified. At some point, authorities say he dragged her into an alley, choked her with a wire, then stabbed her in her throat and chest.

McCullough was briefly a suspect, like more than 100 others, in the 1950s, but he had an alibi. He told investigators he had been traveling to Chicago to get a medical exam before joining the Air Force. He settled in Seattle, working as a Washington state police officer.

As the months became years, many Sycamore residents assumed the killer must have been a transient — perhaps a truck driver passing through.

A deathbed accusation by McCullough’s mother in 1994 — passed on to police by his half sister in 2008 — led to a chain of events that brought about his conviction.

His mother, Eileen Tessier, had lied to police canvassing the neighborhood in 1957 about her son’s whereabouts, buttressing his alibi, prosecutor Julie Trevartchen said Friday.

“She knew what she did and she didn’t want to die with that on her conscience,” she said.

McCullough’s girlfriend in the 1950s also contacted police with evidence that called his alibi into question. She had found his unused train ticket from Rockford to Chicago for the day Maria disappeared.

The case seemed a long shot — at least at the beginning.

DeKalb County State’s Attorney Clay Campbell was taken aback when investigators told him they had a suspect in a 1957 murder. “When they said 1957, I said, you mean 1977? 1997?” he said Friday.

McCullough was arrested on July 1, 2011, in Washington state at a retirement home where he worked as a security guard.

One reason authorities felt confident they had the right suspect was that Maria’s friend, Chapman, picked out McCullough as the teen who identified himself as “Johnny” while the girls were playing. Chapman last saw Maria with that man before the girl vanished.

“I never stopped looking for Johnny’s face,” she said Friday.