Isaac Newton's résumé is one of the most extensive in history, taking part in everything from physics, astronomy, philosophy, theology, alchemy, and even law enforcement! Newton was a warden of the Royal Mint and worked vigilantly to cut down on counterfeiting. He estimated 20 percent of the coins the 17th century were counterfeit.
Counterfeiting was a severe crime, the punishment for which was being hanged, drawn, and quartered. Newton would disguise himself as a commoner in bars and taverns gathering evidence and attempting to catch counterfeiters. He conducted over 100 cross-examinations against witnesses, informers, and suspects in a one-year period and was successful in charging 28 coiners.
His most famous case was against a man named William Chaloner. Chaloner had a routine scheme in which he set up Catholics as conspirators who he would then arrest. He made a small fortune off of this and became a respected gentleman, and even convinced Parliament to allow him to oversee the production of new coins.
While in this position, he greatly expanded the production of false coins, until Newton uncovered his scheme. He put Chaloner on trial for counterfeiting, for which he was later executed for treason, solidifying Newton's position as warden of the Royal Mint.