Thirty-five years ago, violinist Roman Totenberg left his Stradivarius in his office at the Longy School of Music in Cambridge, Massachusetts while greeting well-wishers after a concert. When he came back, the prized instrument was gone.

Totenberg died three years ago at age 101 and never saw his longtime "musical partner,” as he called it, again. At the time, the musician had a hunch about who stole the violin—an aspiring violinist named Phillip Johnson, who was some four decades younger—but there wasn’t enough evidence to pursue it. Consequently, the case went unsolved until several weeks ago when Totenberg’s daughter, Nina, got a phone call from FBI Special Agent Christopher McKeogh.

"I really could hardly believe it at the time," said Nina, who is also the legal affairs correspondent for NPR. She told the Associated Press, "I said, 'I have to call my sisters. I'll tell them not to get their hopes up,' but he said, 'You don't have to do that. This is the violin.'"

It was indeed. The Ames Stradivarius (named for violinist George Ames) had been rediscovered after the former wife of Philip Johnson brought it to New York to have it valued. Johnson died in 2011 and his ex-wife found the violin while cleaning out his belongings. She and her boyfriend broke the combination lock on the case and found the instrument with the label inside saying it was made in 1734 by Antonio Stradivari. They had no idea it was stolen.

Before he even saw the violin in person, appraiser Phillip Injeian had seen photographs from Johnson’s former wife and through his own research into the Violin Iconography of Antonio Stradivari had learned that a 1734 violin belonging to Roman Totenberg was stolen and lost over three decades ago. After checking out the goods up close, Injeian told Johnson’s ex-wife to contact the authorities immediately.

Yesterday at the U.S. Attorney's office in New York, the violin was returned to the Totenberg sisters in a formal ceremony under an agreement filed in federal court. It’s one of roughly 550 Stradivarius violins still in existence today. While it’s difficult to speculate on the value, a 1721 piece sold for nearly $16 million at auction in 2011.