A hoard of more than 1,400 artworks found in Germany and at least partially seized by Nazis includes a previously unknown piece by Marc Chagall and works by some of the masters of the 20th century, authorities said.
Investigators searched the apartment in an upscale Munich district in February 2012, as part of a tax probe that started with a routine check on a Zurich-Munich train in late 2010.
Authorities said they found 121 framed and 1,285 unframed works - including by 20th century masters such as Pablo Picasso, Max Liebermann and Ernst Ludwig Kirchner and earlier works by artists including Henri de Toulouse-Lautrec, Gustave Courbet, Auguste Renoir and Canaletto. The oldest work dates back to the 16th century.
Prosecutor Reinhard Nemetz told reporters that investigators have turned up "concrete evidence" that at least some of the works were seized by the Nazis from their owners or classed by them as "degenerate art" and seized from German museums in 1937 or shortly after.
"Degenerate art" was largely modern or abstract works by artists that the regime of Adolf Hitler believed to be a corrupting to the German people. Their "deviant" characteristics were often attributed to Jewish corruption.
Officials are investigating whether the suspect in the case was in wrongful possession of the paintings. They wouldn't identify him and said they don't know where he is.
The paintings were found in one room at the apartment, where they were "professionally stored and in a very good condition," said Siegfried Kloeble, the head of the customs investigations office in Munich. He said it took a specialist company three days to remove the paintings from the apartment. Officials refused to specify where they are being kept.
Meike Hoffmann, an expert on "degenerate art" at Berlin's Free University who is helping the investigation, presented pictures of a selection of works from the collection.
They included a painting by Chagall that Ms Hoffmann said isn't included in lists of the artist's work.
"These cases are, of course, of particularly high art history significance for researchers," she said. Experts haven't yet been able to determine where the Chagall came from, she added, describing the research as "very, very difficult."
An unlisted painting by Henri Matisse, apparently dating back to the 1920s, was also presented.