A revolver that killed one of the most famous wanted men in the Wild West 140 years ago is slated to be offered for millions of dollars next month.

Pat Garrett's Colt single action army revolver was used to gun down Billy the Kid.

Prior to his killing, a judge is said to have sentenced famed outlaw Billy the Kid to hang until "you are dead, dead, dead." Billy was rumored to respond, "And you can go to hell, hell, hell."

Legends like these — some facts and others fiction — chronicling the Kid's life have persisted more than 100 years after his death. And they've kept history buffs captivated by Billy the Kid's tale. They have also driven interest in pieces of Wild West history, for which collectors are prepared to pay hefty prices. In 2008, for instance, Bonham sold Billy's gun for $64,350.

Billy the Kid, a gunslinger often said to have killed eight men, had been on the run for three months when Sheriff Pat Garrett hid in a dark bedroom and shot him in the chest on July 14, 1881, in Fort Sumner, N.M., according to Garrett's account. The single action revolver Garrett used will be offered at Bonhams auction house, which estimates it could go for $2 million to $3 million. Garrett had taken the gun from another member of the Kid's gang, Billy Wilson, after he arrested him.

Pat Garrett signed a book contract in 1881 for publication of The Authentic Life of Billy, the Kid.

As one of the era's most notorious figures, the legend's life has frequently been dramatized in American popular culture. A 21-year-old when he died, Henry McCarty, who became known as Billy the Kid, has been depicted as both villain and hero in countless songs, films and books.

The Authentic Life and Death of Billy the Kid, a biography and partly first-hand account written by Garrett, has been criticized for embellishing the truth but is generally acknowledged to be factual.

Most retold was his unexpected bond with Garrett — they were ranch hands that shared a friendship before the months-long pursuit, according to Williamson. Even now, the details surrounding Billy's death remain elusive. Some speculate that Garrett never actually killed Billy, but allowed him to escape. Decades later, at least two men were believed by some to be Billy.

The weapon is expected to be sold to an avid collector for more than $3 million.