Experts now believe a photo purchased at a flea market for $10 showsstanding with the lawman who ultimately killed him, making the snapshot potentially worth millions.
Frank Abrams, a North Carolina attorney, first spotted the tintype photo in Asheville in 2011. The self-described history buff said the group picture of five men was part of a set and sat on his wall for several years.
"Now, it's in a safe deposit box," Abrams told The Associated Press in a phone interview Tuesday. "I don't travel with it."
After seeing a TV program in 2015 about the discovery of a photo of the outlaw playing croquet, Abrams was inspired to research him further. That's when he thought he recognized Pat Garrett,'s former friend and the sheriff who gunned him down.
Abrams approached Robert Stahl, a retired professor emeritus at Arizona State University who is no stranger to the history of Billy the Kid. In 2015, Stahl filed a petition in New Mexico Supreme Court in pursuit of a death certificate for the Kid, also known as William Bonney, from the state's medical examiner.
Stahl said he thought it was a "high probability" that it was Garrett in the photo, but he wasn't sure if another man was Billy the Kid.
"I told him, 'The biggest thing you could do right now is get the picture out and let people look at it and give you feedback,'" Stahl said. "To me, it's one of the most intriguing and historically significant of those tintypes of the Old West."
Abrams, who lives in Arden, told CBS News affiliate KRQE-TV that he spent the next several months consulting various forensic experts. Several said the tintype was likely taken between 1879 and 1880, which coincides with the Aug. 2, 1880, date someone had written on the photo, Abrams said. A Los Angeles forensic video expert said facial recognition software indicates that it is most likely Garrett and Billy the Kid in the picture, according to a signed declaration. A handwriting expert in Texas compared a signature from Garrett on the photo with 10 documents with his known handwriting. He declared them matching in a notarized letter in September.
"People ask me all the time, what do you think it's worth, what do you think it's worth? I won't put a price on it, quite frankly. It's priceless," Abrams told KRQE-TV.
The Kid and Garrett were close friends until Garrett became Lincoln County sheriff. Garrett ended up fatally shooting the outlaw in Fort Sumner in July 1881.
The photo of the Kid discovered in 2015 has since been estimated to be worth $5 million. Experts believe a picture that shows the New Mexico outlaw with Garrett would be worth much more. However, Abrams isn't interested in finding out anytime soon.
"One day it may end up at an auction house somewhere. We'll see what happens," Abrams said. "Right now, that is not the first thing on my mind. I've always been somebody who's interested in history and background."