After interviewing about 130 witnesses and combing through more than 100,000 pages of documents, prosecutors have dropped their year-old investigation of sexual-abuse allegations against former Syracuse University assistant basketball coach Bernie Fine, federal authorities said Friday.

The probe "revealed insufficient evidence to pursue federal criminal charges," said Richard Hartunian, U.S. Attorney for the Northern District of New York, concluding an investigation that cost Mr. Fine a job he had held for 35 years.

"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," Mr. Hartunian said.

Mr. Fine, 66 years old, couldn't immediately be reached for comment.

His attorneys, Karl Sleight and Donald Martin of Harris Beach and David Botsford of Botsford & Roark, said in a statement they were "not surprised" by Mr. Hartunian's decision, and that they "greatly appreciate his decision to publicly announce that decision." They said that "the damage inflicted upon Bernie and his family is simply immeasurable."