John Tunstall is murdered by outlaw Jesse Evans, sparking the Lincoln County War

Jesse Evans

(Wikipedia) The Lincoln County War was an Old West conflict between rival factions, which began in 1878, in New Mexico Territory, the predecessor to the modern state of New Mexico, and dragged on until 1881.
The feud became famous because of the participation of Billy the Kid. Other notable figures included Sheriff William Brady, cattle rancher John Chisum, lawyer and businessman Alexander McSween, James Dolan, and the man who started the problem, Lawrence Murphy. Continued