The film director's staff contacted the FBI weeks ago after seeing a bulletin from the agency's Art Crime Team seeking clues about the theft of the "Russian Schoolroom" oil painting, the Los Angeles Times said Saturday.
Special Agent Chris Calarco of the FBI's Art Crime Team and Jessica Todd Smith, curator of American art for the Huntington Library, inspected and authenticated the painting Friday afternoon at Spielberg's offices on the Universal Studios lot.
Sources close to the investigation said it is worth between $700,000 and $1 million. The painting of schoolchildren in a classroom looking at a bust of Soviet leader Vladimir Lenin was stolen during an exhibit at an art gallery in Clayton, Mo., in June 1973.
"He's an absolutely unknowing victim in this," Calarco said of Spielberg.
Spielberg bought the painting from an art dealer in 1989, Calarco said. The Oscar-winning director is a Rockwell collector who helped found the Norman Rockwell Museum in Stockbridge, Mass.