In 1877 Billy was in a saloon when he got into an argument with a blacksmith, Francis "Windy" Cahill. Francis had bullied Billy on many occasions calling him a “pimp” and Billy responded by calling him a not so nice name. This caused them to brawl and they fought for Billy’s revolver, but Billy got to it first and severely wounded Francis so bad to where he died the following day.
Billy claims to have killed 21 men. One for every year he lived, but experts believe it was anywhere from 4 to 9 on his own and 5 with help from others.
He was finally arrested in 1880 for the killing of Sheriff Brady. After being sentenced to death, he killed his two guards and escaped in 1881. He was hunted down, shot, and killed by Sheriff Pat Garrett on July 14, 1881, in Fort Sumner, New Mexico.
Not too long after Garrett killed Billy, he wrote a biography about the young outlaw, titled “The Authentic Life of Billy, the Kid.” The book was the first of many and many people loved it.