"The nature and seriousness of these allegations, which involved conduct typically committed in private with individuals who are reluctant to come forward, warranted a thorough federal investigation," Hartunian said.

It's unclear whether Fine, 66, could get his job back.

His lawyers, Karl Sleight, Donald Martin and David Botsford, said in a statement that they were not surprised by the decision.

"The damage inflicted upon Bernie and his family is simply immeasurable," the lawyers said. "Bernie hopes and prays that the lesson learned and remembered is that a rush to judgment has irreversible consequences."

The investigation erupted in the glare of a spotlight on child abuse shone by the Penn State University scandal, which broke shortly beforehand. Two former Syracuse ballboys, Bobby Davis and Michael Lang, came forward Nov. 17 and accused the longtime assistant of fondling them when they were teens. Davis said the sexual contact continued for years.

But the claims by Davis and Lang had happened too long ago to be prosecuted. Ten days later, though, a third man, 23-year-old Zachary Tomaselli, of Lewiston, Maine, went public with an accusation that Fine had molested him in 2002 in a hotel room when the team played in Pittsburgh. The same day, ESPN aired an audiotape in which Fine's wife, Laurie Fine, apparently acknowledged to Davis she knew about the molestation he alleged.

Bernie Fine, who denied the allegations, was fired Nov. 27, and the federal government began investigating Tomaselli's claim, the only one that fell within the statute of limitations. The federal statute of limitations that went into effect in 2002 allows prosecution until the victim reaches age 25; Tomaselli was 23 when he made his claims.

Hartunian, in his statement, said closing the investigation doesn't mean something did or did not happen, only that there wasn't enough admissible evidence to get a conviction. He said that people should come forward with tips if they have any more information.

Davis had made the same accusation against Fine to the university and Syracuse police a decade before, but the police couldn't investigate because of the statute of limitations, and the school said its probe turned up no evidence of wrongdoing. Davis did not immediately return a call seeking comment Friday.

From the start, there were doubts.

When Davis and Lang came forward in November, Boeheim angrily defended his assistant of 35 years and said the accusers were only out for money, seeking to cash in on the publicity generated by the Penn State scandal, in which former assistant football coach Jerry Sandusky was charged with sexually abusing several boys.

Another accuser, Floyd Van Hooser, said Fine abused him for years but later said he was lying.

That left Tomaselli, who was accused of sexually abusing a boy at a camp in 2010 and whose father had said the boy was lying. Tomaselli, who eventually was convicted of sexual abuse and started a prison sentence of three years and three months in April, insisted Friday that he was telling the truth about Fine.

Before he went behind bars, Tomaselli took the media on a wild spin, repeatedly lying in a bid, he said, to keep his name in print:

• He said Fine had made harassing phone calls to him, and he got an order of protection. Then he said that was a lie.

• He said he had lied about the whole thing, that Fine had never touched him.

• He reverted to his old claim and insisted Fine abused him.

Tomaselli said Friday by phone from the Maine Correctional Center in Windham, Maine, that he had a "mental breakdown" when he recanted. He said sports figures have too much power and that may contribute to no one believing him, and he thanked law enforcement officials for thoroughly investigating his allegations even after his credibility was called into question.

There were other sordid claims to come out, including that Fine's wife had sex with players and that Boeheim knew, or should have known, of his assistant's behavior.

While his No. 1-ranked Orange continued to rack up wins -- they wouldn't drop their first game until Jan. 21 -- Boeheim endured criticism and scrutiny and was questioned during news conferences about the case.

Boeheim, who just completed his 36th year coaching Syracuse, vehemently supported his longtime assistant when the accusations broke and said Davis was lying. "The Penn State thing came out, and the kid behind this is trying to get money," he told the Syracuse Post-Standard.

Amid criticism from victims' rights advocates, Boeheim apologized and said he spoke out of loyalty and was basing his comments on a 2005 university investigation that failed to corroborate Davis' claims.

Boeheim referred questions to the university's press office. University spokesman Kevin Quinn said that Syracuse appreciated the work done by the U.S. attorney's office and that the decision to fire Fine was appropriate.

"It was made in the best interest of the university," Quinn said.

Davis and Lang sued Boeheim and the university for defamation, but a judge dismissed the lawsuit, saying Boeheim's defense of his friend was clearly opinion.

Attorney Gloria Allred, representing the two men, said, "The DOJ's decision does not indicate that there is or is not merit to the allegations against Mr. Fine, and it does not vindicate him."

Fine, who put his Syracuse home on the market in March, has been in Florida and was recently hired as a consultant for an Israeli basketball team.

Laurie Fine has sued ESPN, alleging defamation and claiming the network knew that Davis was lying and ruined her life. That suit is pending.

The university's prompt response to the allegations was done in good faith but was flawed because, among other things, there was no direct contact with law enforcement, a special committee of the university's board of trustees said in a report released in July.

Davis met Fine in the early 1980s at a park that was a basketball hangout for kids in a working-class neighborhood. After he became a ball boy in 1983 around age 11, Davis said, he went everywhere with Fine.

Fine turned into a father figure, and as Davis spent more time at the older man's house -- actually living there sometimes -- the abuse escalated from touching outside the pants to inside, according to Davis.

During an interview in December with The Associated Press, Davis said the abuse would sometimes occur in Fine's campus office with secretaries just beyond the closed door, at Syracuse basketball camp and at a fraternity house.

Some of the abuse would occur in Davis' bed in Fine's basement while Fine's wife was home, Davis said.