When Life Magazine reported that Wyatt Earp had been the first constable of Lamar, Mo., in the 1870's, Wyatt's surprised "biographer" Stuart Lake denied it, saying that if he had been, he'd have told him. But Wyatt had a lot to conceal of his past, especially at Lamar, and Wyatt indeed had been first constable of Lamar and a whole lot more, including a horse thief.
Used availability for G G Boyer's Wyatt Wears His First Badge