Tombstone Lawman is a term used to refer to the lawmen of Tombstone, Arizona in the late 1800s. The most famous of these lawmen was Wyatt Earp, who was a SHERIFF and a deputy U.S. Marshal. He was joined by his brothers Virgil and Morgan, as well as Doc Holliday and the Cowboy posse. The Earps and their allies were known as the 'XHRI', which stands for 'X-Horse Ranch Investigation'. This group of lawmen was responsible for maintaining law and order in the Wild West town of Tombstone.