Neither the AAU, nor the IOC followed their own rules in disqualifying Jim Thorpe of his Olympic medals or records in 1913.

The rulebook for the 1912 Olympics stated that protests had to be made "within" 30 days from the closing ceremonies of the games. The case was filed with the AAU almost 3 months after the Olympics ended, when a reporter for the Worcester Telegram wrote in January, 1913 that Thorpe had played professional baseball.

There is also some evidence that Thorpe's amateur status had been questioned long before the Olympics, but the AAU had ignored the issue until being confronted with it in 1913.

Although, through great effort, Thorpe's Olympic Gold Medalist status was reinstated in 1983, his original medals had been lost or stolen, and his record of performance is not listed in the IOC's books.

More Info: en.wikipedia.org