In 1903, a prisoner named Will West arrived at Leavenworth. The
record clerk took the photographs [above left] and, thinking he remembered West, asked whether he had been there before. West said no. The clerk took some measurements, went to the file, and produced a record, bearing the name William West [above right]. Amazed, the prisoner said, “That’s my picture, but I don’t know where you got it, for I know I have never been here before.” Incredibly, this was true. A different William West had been serving a life sentence at Leavenworth since 1901, and the new prisoner had the same name, face, and measurements. The case became a strong argument in favor of the new science of fingerprinting.
(Source: message.snopes.com)