Which of the following details about Billy the Kid is INCORRECT?

The 19th century Wild West outlaw Billy the Kid has been denied a pardon 130 years after his death. The possibility was first suggested when historical documents appeared to show that Billy the Kid had been promised a pardon in return for testifying in a murder case.
    Billy the Kid, whose real name was William Bonney, was only 21 when he was shot dead, but his brief life inspired dozens of books and films. It’s not clear how many people he killed; some say more than 20. But his undoubted skill with a gun and his personal charm made him more of a folk hero than a notorious criminal. Supporters campaigned for a pardon, but the Governor of New Mexico Bill Richardson has refused one after extensive research. "The romanticism appealed to me," he said, "but the evidence didn’t support the idea."