FBI art crime agents are currently investigating the origin of artworks from a late socialite’s collection after several pieces were found to have been stolen sometime in the past 30-40 years, reports the Associated Press.

William M. V. Kingsland, a New York socialite and art dealer who passed away in 2006, left an impressive collection of Pablo Picasso paintings and other works behind him but no will.

As no heirs claimed Kingsland’s treasure of art, which included sketches, paintings and sculptures, city officials hired two auction houses, Christie’s and Stair Galleries, to sell off the collection but things apparently did not go according to plan, as at least 20 pieces of art may have been stolen, as FBI art crime agents believe.

The stealing seems to go two-ways. On one hand, reports the AP, Christie’s auction house has discovered that some of the pieces from the collection had been reported stolen in the 1960s and 1970s. This puts the spotlight on Kingsland and the way he obtained the art.

On the other hand, two Picasso paintings went missing during the process of having the collection prepared for auctioning. The movers were apprehended and the art retrieved but the confusion continued.

The FBI is currently trying to figure out who the rightful owners of the various art pieces are.

Among Kingsland’s collection (whose full name is William Milliken Vanderbilt Kingsland but whose birth name was later found to be Melvyn Kohn), are an Alberto Giacometti bust valued at almost $1 million, more Pablo Picasso paintings, as well as works by John Singleton Copley, Fairfield Porter and Odilon Redon.

FBI art crime agent Jim Wynne said Monday the procedure agents deemed best to deal with this case was to “publicize the artwork to the general public,” as the collection is of an “overwhelming size.”

More details were learned about Kingsland after his death, including the fact that he did have relatives but had not spoken to them in years and that he actually lived in a crowded one-bedroom apartment.

Wynne added the FBI had not reached a conclusion yet regarding his identity as “a thief or a good-faith purchaser.”

The agency has posted photographs of some of the artwork on its website.