||Once boasting that his works would never be detected unless he wanted them to be was exposed by accident. A curator from the National Art Gallery in DC had two old master drawings from Sperandio and Cossa. He noticed that the drawings resembled each other and both had the same flowing lines. Hebbron umasked himself to a point and admitted to drawing about 500 old master drawings from 1963 to 1978. In 1978 he changed his style and became even harder to detect. Hebbron died in Rome in 1996.