The New York Post said dozens of works of questionable ownership were found in the apartment of late Manhattan art dealer Melvyn Kohn -- who went by the name William Milliken Vanderbilt Kingsland.

Because Kohn didn't leave a will and had no known living relatives when he died in 2006, art auctioneers were called in to sell off the many treasures crammed into his one-bedroom apartment.

However, several pieces the auctioneers attempted sell turned out to be stolen, sparking an FBI investigation, the Post said.

The agency has posted more than 100 items, including three works by Pablo Picasso and one by Henri de Toulouse Lautrec, in hopes of returning them to their legal owners.

"Because of the overwhelming size of the collection, we decided the best and expeditious course of action was to publicize the art work to the general public," FBI spokesman Jim Wynne told the newspaper. "Whether (Kohn) was a thief or a good-faith purchase(r,) we couldn't come to a conclusion on that. All we know is he ended up with the stuff."