A man says he has discovered a piece of American history: a never-before-seen photo of the infamous outlaw Jesse James.

Dale Ball, from California, says the photo was tucked inside an old family heirloom – an old book passed down from his grandfather Richard Marks, who died in the 1990s.

The photo two and a half inch tall photo has been dated by experts to between 1870 and 1874 – when the outlaw was in his late 20s.

Ball, 55, an antique shop owner and cleaning company boss, says he has spent the last few years authenticating it with experts.

And using facial recognition metrics, as well as historical signifiers and context, and comparing it to some of the eight other known James photos, a leading expert and an auction house are both convinced it’s the real deal.

Ball has no idea how his grandfather came to possess the image, but speculates he somehow had ties with the legendary bandit.

James, from the Midwestern state of Missouri, gained notoriety in the 1860s as an American outlaw, bank robber, train robber, and leader of the James–Younger Gang.

He has come to be characterised as something of a Robin Hood-style character despite his crimes, something historians have challenged.

James was shot and killed aged 34 in 1882 by James gang member Bob Ford, who was said to seeking to collect a $10,000 reward offered by Governor Tom Crittenden, as per the St Joseph, Missouri website.

Ball says he plans to auction off the photo in the coming weeks and hopes it will fetch $500,000 (around £386,250).

“It’s truly an amazing find,” he said. “The clarity is unreal. The clothing and setting have been authenticated.”

Ball’s grandfather, Richard Marks, died in his mid 90s and was a citizen on patrol – a volunteer which assists law enforcement to report suspicious activity.

The photo was inside an old green book which had always been in Marks’ home, in upstate New York – brought from his home in California – which the family thought was a Death Registry for the town of Deadwood.

Inside the book, Ball found a series of old tintype photos, also known as ferrotypes, but one image stood out.

“I recognized the man in the photo, but I couldn’t quite place who it was,” he said.

It wasn’t until 2019 that Ball realized what he had – when he started selling antiques and showed the image to dealers.

“One of them looked at my photo and said, ‘Holy crap, that’s Jesse James’,” said Ball. “I was blown away. We started researching, and sure enough, there was no question.”

To authenticate the image, Ball turned to Ron Pastore, who has was involved in a university-led exhumation of remains once-thought to be the bandit, and presented his findings to the American Academy of Forensic Science in 2004.

Pastore, has authored a number of books and taken part in A+E History Channel documentaries on the robber, and has the largest private collection of Wild West outlaw photographs – some 3,000 tintypes.

Ron’s report gives it an authenticity score of 98%. According to the report, tests date the photo to late 1870s and it was found among a group of photos of people who have “kinship” to the James’ family – including people said to be his father Robert, his brother Frank and his wife Zerelda Mimms.

It says historical records reveal Jesse was in California – where the box was found – as a man, and the man the picture is wearing “period appropriate” clothing.

Using other photos of James he says Dale’s photo has the tell-tell physical features of James, including:

• a cleft in his eyebrow
• sagging eyelid on the outer right side
• a flat nostril on the right side
• fat buckles below the corners of his mouth
• large eye orbits and irises

As well as noting his shoulders slope at the same angle, and a similar almond shaped hear, he mapped the facial features in the photo, and a number of other known photos and concluded the eyes, head height, nose, mouth and chin match in placement – horizontally and vertically, and when overlayed.

He even concludes a “bulge” under the jacket on the right side could be a concealed weapon in a shoulder holster.

Ron 71, from Wichita, Kansas, who works with law enforcement agencies on crime scene investigation, admits he was initially sceptical.

“Initially, I told Dale, ‘I’m going to study this and do a preliminary test before I agree to do the evaluation because I don’t take them if I don’t think it’s going to be a positive outcome,'” he recalled.

“And it took me a couple days and I went ahead and did some preliminary work on it and it had a good score.

“I called him back and said, ‘Yes, I think you’ve got the real McCoy here.’ So we ran it through the evaluation process. The overlays are really impressive.

“So the biometrics and all of these different metrics that we use to evaluate gave him a score of 98%.”

Pastore added: “One of the things I keep in mind when I’m looking at photographs of Jesse James is that he was an outlaw and was trying to disguise his identity.

“But he has some very unique facial characteristics,” he explained. “The face is not symmetrical, one nostril is different than the other. One eye is different than the other.

“And so that’s part of my evaluation process was looking at each facial feature independently and then seeing it as a whole.”

Ball says he has been approached by major auction houses. Jim Weigl, auctioneer and owner of Blue Box Auction Gallery in Norfolk, Virginia, describes the photo as a “remarkable piece.”

“The nature of what we do is connect people that have amazing, interesting, unique items with people who collect interesting items,” Weigl explained.

“The nature of our auction determines the true market value of the individual item. We recently sold two soup bowls recovered from the wreckage of the Titanic.

“An important part of what we do is to present the information from what we have and utilize third-party and in-house experts to determine the legitimacy of the item.

“Dale’s Jesse James photo is an absolute part of American history and an absolutely fascinating piece.”

“To have a photo like this, with solid provenance and authentication, is a dream,” Ball said. “I grew up watching Westerns with my grandparents — Clint Eastwood films, all the classics.

“I never imagined I would own something like this. It’s truly astonishing.”

As he contemplates the future of the Jesse James photo, Ball remains in awe of its significance.

“This photo deserves to be seen,” he said.