Western outlaw Billy the Kid met his demise at about 12:30 a.m. on July 14, 1881, when he went to his friend Pete Maxwell’s home in Fort Sumner, New Mexico in search of a slice of beef for a late-night snack.

As the story goes, Billy—just 21 years old, but already a murderer who had escaped from jail and killed two guards in the process—made the mistake of walking into a darkened bedroom, where Lincoln County Sheriff Pat Garrett was questioning Maxwell. Both Garrett and Billy were armed, but Garrett shot first, killing Billy.

At least, that’s the most widely-accepted version of events. But over the years, some of the murky details surrounding the death of Billy—whose real name probably was Henry McCarty, though he later went by the alias William Bonney—have proven to be fertile ground for alternative theories.

Some have claimed that Garrett shot the wrong man and Billy escaped. To complicate matters further, at least two men emerged decades later who were believed by some to be Billy.

As Dale L. Walker details in his book Legends and Lies: Great Mysteries of the American West, one prospective Billy was John Miller, a farmer and horse trainer who lived in a small village in New Mexico near the Arizona border and died in 1937. (His few possessions reportedly included a pistol with 21 notches on the grip, the same as the number of killings that some accounts attribute to Billy. The other, a resident of Hico, Texas named Ollie “Brushy Bill” Roberts, actually managed to get a meeting with the governor of New Mexico in 1950, in which he unsuccessfully sought a pardon for Billy’s murders. He died soon afterward.

The persistent belief that Billy the Kid survived and hid out somewhere shouldn’t be too much of a surprise, explains Jim Motavalli, author of The Real Dirt on America’s Frontier Outlaws, that examines the legends and the reality of various famed desperados of the American West. After all, similar stories have arisen after the deaths of other people who captured the public imagination, from Elvis Presley to Adolf Hitler.

“Things like this typically start out as bar stories,” Motavalli says. “You want someone to buy you a drink, so you say, ‘I’m Billy the Kid.’”

To add to the confusion, the actual facts about Billy the Kid haven’t been easy to come by. Details of his early life are sketchy, and much of what was written about him just before and after his death was what Motavalli calls “scurrilous literature”—sensationalized newspaper accounts and quickie books churned out by publishing houses. “They didn’t do a lot of actual research when they did these biographies,” Motavalli says.

The 1882 biography The Authentic Life of Billy the Kid, Noted Desperado of the Southwest, Whose Deeds of Daring and Blood Made His Name a Terror in New Mexico, Arizona and Northern Mexico, which was written by Garrett, his killer, contains what seems to be the most credible account of the fatal confrontation, according to Motavalli. Instead of depicting an epic gunfight out of a dime novel, Garrett makes his shooting of the outlaw seem like an incredibly lucky break.

That night, Garrett wrote, he and two deputies, John W. Poe and Thomas McKinney, went to the ranch where Maxwell lived. A short distance from the property, Poe spotted an acquaintance who was camped out, and the lawmen dismounted and stopped to have coffee with him before heading on foot through an orchard to the house. Then they heard voices in Spanish—a language that Billy the Kid spoke as well as English and the Gaelic of his parents’ native country, Ireland.

The three men concealed themselves, as a man in a broad-brimmed hat, a dark vest, shirt and pants walked past them. Though they didn’t realize it, the man was Billy the Kid, who was headed for the house with the intention of carving for himself a piece of beef.

Leaving the two deputies on the porch, Garrett slipped into the darkened house and quickly found the room where Maxwell was in bed. Garrett began questioning him, and Maxwell admitted that the outlaw had been around, though he wasn’t sure where he was at the moment. Just then, a figure appeared in the door, carrying a gun and a butcher knife, and asked in Spanish who was there.

“Who is it, Pete?” Garrett whispered to Maxwell.

“That’s him,” Maxwell responded.

Billy the Kid realized that someone besides Maxwell was there in the darkness, and raised his pistol within a foot of Garrett’s chest. “Who’s that?” he asked, in Spanish.

Garrett quickly drew his revolver and fired two shots. The first shot hit Kid in the chest. “He never spoke,” Garrett recalled. “A struggle or two, a little strangling sound as he gasped for breath, and The Kid was with his many victims.”

When Garrett and the deputies examined Billy the Kid’s gun, they found that he had five cartridges and one shell in the chamber, with the hammer resting on it. If he hadn’t hesitated, Garrett might have been the one lying dead on the floor.

“It was the first time, during all his life of peril, that he ever lost his presence of mind, or failed to shoot first,” Garrett wrote.

The next day, according to Garrett, a Coroner’s Jury held an inquest, determined that the dead man was Billy the Kid, and ruled that Garrett’s killing of him had been a justifiable homicide. The outlaw’s body was buried that same day. Garrett noted that the corpse went into the grave fully intact, in order to discredit opportunists who were exhibiting skulls, fingers and other body parts that they claimed had belonged to Billy the Kid. “One medical gentleman has persuaded credulous idiots that he has all the bones strung upon wires,” Garrett wrote with disdain.

Unfortunately, the body isn’t available for exhumation and DNA comparison with Billy the Kid’s mother Catherine Antrim, who is buried in Silver City, New Mexico. That’s because the grave markers in Fort Sumner’s Old Military Cemetery were washed away in a flood in September 1904, according to Richard Melzer’s book Buried Treasures: Famous and Unusual Gravesites in New Mexico History. A few decades later, three of Billy the Kid’s surviving pallbearers were asked to help locate the spot where their friend had been buried, but they picked three different graves.

As a result, “it’s impossible to tell which of the bodies in the cemetery are his,” Motavalli says.

Retired Arizona State University history professor Robert J. Stahl tried unsuccessfully in 2015 to convince New Mexico officials to issue a belated death certificate for the outlaw, but his petition was rejected by the state’s Supreme Court. He also compiled a detailed list of the witnesses who saw the outlaw’s body after his death and before his burial. Instead of hiding the body, “Garrett’s intention was to let people see whom he had shot and to let those who desired pay their final respects to this much–liked young man,” Stahl noted.

That fact points to the likelihood that Billy the Kid was indeed killed that night in Fort Sumner, in the manner that Garrett described.

But that still isn’t likely to dispel the rumors. As Motavalli explains, “People are always willing to believe alternative theories.”