An outgoing US state governor hinted that he could soon give a posthumous pardon to Billy Kid, the infamous 19th-century Wild West outlaw.

New Mexico Governor Bill Richardson, who stands down next month, said his office had received a formal petition, which he will consider and make a decision on before the end of the year.

“As someone who is fascinated with New Mexico’s rich history, I’ve always been intrigued by the story of Billy the Kid and, in particular, the alleged promise of a pardon he was given by Territorial Governor Lew Wallace,” he said.

“I will diligently review this new petition and all the facts available regarding an agreement between Billy the Kid and Governor Wallace before rendering any decision,” he added.

The legend of Billy the Kid – real name William H. Bonney, although also known as Henry McCarty and Henry Antrim – has inspired dozens of books and films, several impostors and attempts to exhume his grave to test for DNA.

Some say Wallace, who wrote the novel Ben Hur from the Palace of the Governors in Santa Fe, promised to pardon Bonney, shot down by Sheriff Pat Garrett on July 14, 1881.

Garrett’s grandchildren oppose granting a pardon.

It would amount to painting Garrett as a cold-blooded killer, “accusing our grandfather, in national and international media, of hideous crimes,” wrote Jarvis Patrick Garrett of Albuquerque and Susan Floyd Garrett of Santa Fe.

“We consider that an abomination as well as an inexcusable defamation of a great man.”

But William Wallace, the former governor’s great-grandson now living in Westport, Connecticut, recently said there is no historical evidence to back that up.

Pushing for the pardon for more than a decade have been various fans of the Billy the Kid legend, including Elbert A. Garcia of Santa Rosa, New Mexico, who believes he is the great-grandson of Billy the Kid.