Billy the Kid: Experts say photograph showing Wild West outlaw is genuine and could sell for $5m

The image is to be the focus of a forthcoming documentary

The image is believed to be one of just two known to exist of the outlaw (Kagin's )

The image is grainy, the details imprecise.

But a rare coin dealer in California has concluded the 4x5-inch tintype purporting to show legendary gunman Billy the Kid playing croquet, is the real thing. The company is currently negotiating a private sale of the photo and hopes to fetch $5m.

What may be more remarkable is that the picture - one of just two believed to exist of the outlaw - was bought for just $2 a part of a miscellaneous lot at a Fresno junk shop.

“When we first saw the photograph, we were understandably skeptical - an original Billy the Kid photo is the Holy Grail of Western Americana,” David McCarthy, an expert with Kagin’s, the company selling the image, said in a statement.

“We had to be certain that we could answer and verify where, when, how and why this photograph was taken. Simple resemblance is not enough in a case like this - a team of experts had to be assembled to address each and every detail in the photo to insure that nothing was out of place.”

(Kagin's)

He added: “After more than a year of methodical study including my own inspection of the site, there is now overwhelming evidence of the image’s authenticity.”

Billy the Kid was one of two nicknames used by Henry McCarty - the other one being William H Bonney. McCarty was an outlaw whose story has become inextricably linked with legend, some of it pushed by Hollywood and the countless books written about him.

It is believed he was killed in the summer of 1881, though reports that he survived the encounter with Sheriff Pat Garrett persisted.

The image being offered for sale depicts Billy the Kid and several members of his gang, The Regulators, relaxing in the summer of 1878. It is to be the subject of a forthcoming two-hour documentary on the National Geographic Channel, narrated by Kevin Costner.

Taken just one month after the tumultuous Lincoln County War came to an end, it offers a rare window into the lives of these gunmen. They look markedly relaxed.

The only other known photograph of Billy the Kid is a portrait of the outlaw taken in Fort Sumner, New Mexico in 1880, the Associated Press said.

It sold for $2.3m to Florida businessman William Koch in 2011 at Brian Lebel’s Annual Old West Show and Auction in Denver. In that photo, the outlaw is carrying a Colt revolver and trademark 1873 Winchester carbine rifle.

When they were first presented with the image, Mr McCarthy said they were not sure it was authentic adding that “if you do an internet search, there will be 20 people who have a photo of some guy that looks like Billy the Kid”.

He said experts began believing the tintype was real after they were able to determine that four people in the photo - using facial recognition software - were those who spent time with Billy the Kid. Then, they began looking for events in which they were all together around that time.

They stumbled upon a diary of Sally Chisum, in which she described a cattle drive featuring all the players in the photo as well as a wedding that took place between Charlie Bowdre - seated on the horse in the photo - and his wife Manuella, the AP said.

The cattle drive helped researchers narrow the location of the photo to New Mexico and the former ranch of one of Billy the Kid’s employers, John Tunstall. To confirm the site of the photo, Mr McCarthy flew out to the site near Roswell and examined a building that turned out to have been built over and around a structure that was actually in the photo.

“I was standing at an angle from the building and I could see the texture of the stucco on the front of the building,” he said. “You could see the vertical wooden supports through the stucco and I looked at the picture and they were in the exactly the same place. I was amazed. That clinched it.”