The portrait La Bella Principessa was presumed to be a 19th-century German painting of a young woman, but thanks to some CSI-style detective work, forensic-art expert Peter Paul Biro has convinced experts that it's actually a Leonardo da Vinci. Biro made his claim by examining a fingerprint on the canvas’ paint, then using multispectral images and a special digital scanner to lift the fingerprint and match it to a fingerprint from da Vinci's St. Jerome in the Vatican. The technical skill, style, and composition of the painting—a chalk, pen, and ink portrait on vellum—support Biro’s claim. Art collector Peter Silverman bought the portrait for a friend in 2007 for $19,000 from art dealer Kate Ganz, who had purchased the painting for the same price. If the painting’s artist is confirmed as da Vinci, it will be his first major work discovered in 100 years, and could be worth at least $150 million.