A Connecticut gallery owner is heading to federal prison for selling artwork he claimed were original pieces by Pablo Picasso and original signed lithographs by Marc Chagall. They weren\u2019t, according to federal prosecutors, and now the gallery owner has been sentenced to more than fours years in prison for selling fraudulent artwork. David J. Crespo, 60, of Guilford was sentenced Jan. 16 in New Haven federal court to 57 months of imprisonment, followed by three years of supervised release. On Sept. 3, 2013, Crespo had pleaded guilty to one count of mail fraud stemming from the sale of an imitation Marc Chagall lithograph. Prosecutors said an investigation showed that Crespo defrauded at least 10 victims out of a total of at least $400,000. In the coming weeks, Crespo likely will be ordered to pay restitution for the fraudulent sales. Owned gallery in Madison Crespo was an art dealer who operated the Brandon Gallery in Madison. According to court documents and statements made in court, over the course of several years, he defrauded customers by falsely representing that artwork he sold were original pieces by Pablo Picasso and original signed lithographs by Marc Chagall. As part of the scheme, Crespo forged numerous documents in order to provide \u201cauthentication\u201d \u2014 or \u201cprovenances\u201d \u2014 of the fakes to his victims, prosecutors said. An investigation revealed that Crespo obtained reproductions of original Chagall lithographs, but represented to potential customers that they were, in fact, original lithographs that had been produced through an artistic lithographic method, and under the direction and authority of Marc Chagall. Chagall was known for his modernist art and died in 1985. He lived in Russia, France and the United States during his life. Sold \u2018original\u2019 to undercover agent In January 2010, Crespo met with an undercover FBI agent at Brandon Gallery. During the course of the conversation, which was recorded, Crespo and the agent discussed a lithograph known as \u201cThe Presentation of Chloe,\u201d which Crespo represented, among other things, was an \u201coriginal lithograph\u201d that was part of a limited edition collection made from \u201cstone plates\u201d from which multiple impressions were made from \u201cthe same plate,\u201d according to court evidence. The agent agreed to purchase the purported lithograph for $2,000, prosecutors said. Provided \u2018Certificate of Authenticity\u2019 In May 2010, prosecutors said, Crespo shipped the purported lithograph along with a \u201cCertificate of Authenticity,\u201d which valued the piece at $12,750 for insurance purposes, stated that the piece was \u201chand signed by Chagall in crayon after the artist personally examined this particular example,\u201d and represented that \u201c[t]his work came from the collection of Richard Riskin, a longtime friend of the artist.\u201d In fact, Crespo had not obtained the purported Chagall lithograph from the estate of Richard Riskin, as no such person existed, and Crespo knew that the piece was not a limited edition original lithograph manufactured under the artist\u2019s direction using stone plates, but was a photo-mechanical production that was removed from a common edition book, federal officials said. Practiced Chagall signatures found In November 2010, the FBI conducted a search of the Brandon Gallery and found packages of Chagall prints and practiced Chagall signatures, according to court documents. On April 3, 2012, Crespo was arrested on a criminal complaint. He has been detained since Dec. 31, 2014, when he was found to have violated the conditions of his release and his bond was revoked. The case was investigated by the Federal Bureau of Investigation and the Madison Police Department, and was prosecuted by Assistant U.S. Attorneys Anthony E. Kaplan and Liam Brennan of the U.S. Attorney\u2019s Office for Connecticut.