''His mother showed him how to carry a violin under his coat and made him practice,'' Ms. Hall said. ''Then he said he started making friends with the doormen at Carnegie Hall and used to offer to fill in for them so they could go have a smoke. That's how he got backstage.''

The two chose Huberman as their victim, Ms. Hall said, because of the quality of his violin and because he was a foreigner who was unlikely to stay in the United States in search of his instrument. Lloyd's, the violin's insurer, paid Huberman $30,000.

Mr. Altman went on to become a violinist with the National Symphony Orchestra in Washington and performed at social occasions and for Presidents and politicians with the stolen Stradivarius.

After Mr. Altman's death in 1985, Ms. Hall consulted experts who confirmed that the violin was indeed the Gibson Stradivarius. Two years later, she returned it to Lloyd's and eventually collected a finder's fee of $263,000 (roughly 25 percent of the $1.2 million that British violinist Norbert Brainin paid Lloyd's for the instrument in February 1988.)

But instead of going into Ms. Hall's pocket, that money should have been considered a part of Mr. Altman's estate, Ms. Schoenwetter says.

''Hall had a responsibility under common law to treat all assets of the deceased -- including the violin -- as his,'' said her lawyer, Christopher Donohue, speaking for his client, who declined to comment.

Despite its elements of intrigue, Mr. Donohue described the case as fairly straightforward.

''Since the finder's fee was derived from Altman's possession of the violin at the time of death,'' Mr. Donohue wrote in his brief for the Connecticut Supreme Court, ''the subsequent right to the finder's fee is also possessed by the estate.''