'Nude Mona Lisa' perhaps by Leonardo

(ANSA) - Paris, September 29 - The 'Nude Mona Lisa', a charcoal drawing made between 1485 and 1538 and kept in the Museo Condé of France's Chantilly Castle, may have been executed by Leonardo da Vinci himself, experts now think.
    In order to shed light on the mystery, the work was taken in secret a month ago to Paris, where a group of researchers from the Louvre are carrying out a series of tests, Le Figaro said.
    The painting was acquired in 1897 by Henri d'Orleans, Duke of Aumale, who was convinced it was painted by Leonardo.
    Although the experts are still being cautious, Condé Museum curator Mathieu Deldicque says that "the drawing is, at least in part, the work of the master".