New York (AP) – A New York City art dealer who bought the contents of a storage locker filled with paintings for $15,000 says he got more than he bargained for.

He found half a dozen paintings he believes were done by artist Willem de Kooning, a painter whose works have sold for millions of dollars at auction.

The New York Post reports David Killen bought the contents of the locker last year. The paintings were originally from the studio of Orrin Riley, an art conservator who died in 1986, and his partner, Susanne Schnitzer, who died in 2009.

The paintings aren’t signed, but Killen reached out to an expert who was confident they were done by de Kooning, an abstract expressionist originally from the Netherlands who moved the United States.

David Killen, right, and Lawrence Castagna, an art-restoration expert