I am reading a book called King of Heists: The Sensational Bank Robbery of 1878 that Shocked America. The main character in the book is George Leslie, the 19th century bank robber.

Probably a lot of what is written about George Leslie since his death is exaggerated or romanicised so it is difficult to tell at this point what is fact and what is fiction. I would like your opinion on a device that George Leslie is supposed to have invented called the "Little Joker." The Little Joker was described vaguely as consisting of a metal disk and some wires. In the book he carried it in his wallet which I believe were a little larger in the 19th century than they are now.

Supposedly, George Leslie would sneak into a bank and slip the Little Joker behind the combination knob. After that, every time the safe was opened a little wire would wear a groove into the disk. Later they would examine the grooves and try the three numbers where the grooves were deepest in every sequence until the safe opened.

Newspaper articles written about his robberies do not mention this device. I have found references to a brand of tobacco called Little Joker and "Keeler's Little Joker Pat. Nov. 12, 1876" which was a type of rubber stamp.


So, can anyone tell me more about George Leslie's "Little Joker?"