Picture credit: Bonhams New York

The ‘Wanted’ image was issued by the Pinkerton National Detective Agency which had pursued the legendary American train and bank robber – eventually forcing him to flee to South America with his fellow outlaw who was known as the Sundance Kid.

The ‘extremely rare’ mug shot photo of Cassidy, whose real name was Robert Leroy Parker, is expected to fetch $20,000-30,000 at Bonhams in New York on 7 April.

‘This photograph, in which Cassidy looks handsome but undeniably shifty, was taken after his first arrest. It was in Wyoming for stealing horses,’ states the auction catalogue.

‘Within months of his release he formed the Wild Bunch, joining up with the “Sundance Kid”, and went on to rob multiple trains and banks.’

Many believe that Butch Cassidy faked his own death in 1908.