Jesse James had lived through shootouts and two gun blasts to the chest, but ultimately he couldn’t survive a little housekeeping. As the infamous Wild West outlaw straightened and dusted a picture hanging on the living room wall of his rented home in St. Joseph, Missouri, on April 3, 1882, Robert Ford edged up behind him and drew his revolver. A new recruit to the James Gang that had robbed banks, stagecoaches and trains across Missouri and surrounding states, Ford pulled the trigger and fatally shot James in the back of his head.

Now, more than 130 years after Ford betrayed his fellow gang member for the reward money and a gubernatorial pardon, a full-body photograph purported to show James sitting side-by-side with his eventual killer has been authenticated by a renowned forensic artist. The undated tintype photograph was reportedly once in the possession of John and Pauline Higgins, a couple who harbored members of the James Gang in their Cedar County, Missouri, farmhouse during the 1870s. The photograph was handed down through five generations of the family until it came into the possession of 40-year-old Sandra Mills, who lives in rural Washington.

In an interview with the Houston Chronicle, Mills said her grandmother, Isabelle Klemann, told her stories about their ancestors’ connection to the James Gang and kept the tintype wrapped in a handkerchief in her dresser drawer. “This is Jesse James and the coward Robert Ford,” Klemann told Mills of the photograph, which she bequeathed to her granddaughter three years before her 2006 death.

According to Mills, Klemann hoped that her granddaughter could sell the family heirloom and purchase land with the earnings. However, Mills found collectors were skeptical of the photograph’s authenticity. “I’m just a farm girl, so nobody wanted to listen,” she told the Houston Chronicle. “We got no respect from anybody.”

Earlier this year, Mills turned to Lois Gibson, one of the country’s top forensic artists and an analyst for the Houston Police Department, for help. Over her 33-year career, Gibson has worked on more than 4,500 cases, and her sketches based on witness testimonies has resulted in the identification of more than 1,200 individuals. The certified forensic artist has also delved into the realm of history by identifying the sailor who kissed a nurse in Times Square in an iconic photograph at the close of World War II as well as authenticating a rare photograph of another famed outlaw—Billy the Kid.

Mills e-mailed a scan of the tintype to Gibson, who spent a week analyzing the minute details of the two men depicted and comparing them to verified photographs of both James and Ford. When the forensic artist transposed four photographs of James on top of the man in the tintype, she found that all of the facial features—from hairline to nostril shape to the distance between the nose and upper lip—were a match. Gibson even noted that photographs of James show that his left eye is bigger and his left eyebrow is longer than those on his right, and the man in the tintype exhibits the same slight anomalies. “All the features line up nearly perfectly,” Gibson wrote on her Facebook page. “The nose, eyes, lips, forehead and chin are the same size, shape and positioning relative to the other features.”

Gibson also saw a correlation between the tintype and other full-body photographs of James sitting in a chair that went beyond identical shirt and pants styles. “These photos show a remarkably similar hand, arm and leg positioning,” she wrote, noting that photographic subjects in the 1870s and 1880s needed to hold a pose for a full minute. “This natural body position had to be a comfortable one that Jesse James would repeat should he need to hold still so long again.”

The clincher for Gibson was the resemblance between the man sitting on the left in the photograph to the outlaw’s betrayer. “Greatly enhancing the claim that this tintype is truly Jesse James is the fact the man sitting next to him looks remarkably like a known companion in crime, Robert Ford,” she wrote.

Gibson told the Houston Chronicle that the project was the most exciting identification that she had ever done. “This is it, just huge, like finding a T-Rex leg bone,” she said.

It may take more than Gibson’s declaration, however, to convince collectors that this tintype is the real deal, and a great deal of money could be at stake. The only authenticated photograph of Billy the Kid sold for $2.3 million at a 2011 auction, and Bobby Livingston, executive vice president of RR Auction, told the Houston Chronicle that the tintype could fetch a similar price if authenticated. “It’s compelling,” he said of Gibson’s findings, “but I would want to see much more analysis.”

The forensic artist, however, has no doubt about the identity of the man in the tintype. “I know faces inside and out, and I worked exhaustively on this,” Gibson told the Houston Chronicle. “I am positive it’s Jesse James.”

Eric James is a member of the James family who together with one of the outlaw’s great-grandsons co-founded the James Preservation Trust in 2002. Their mission is to archive and address issues of veracity in regard to the family history and they are among the Jesse James historians who disagree with the authenticity of this photo. He says the tintype is just another in a long line of hoaxes related to the gang leader.

James tells HISTORY the trust receives photograph representations two to four times a month. In a lengthy post on Stray Leaves, the official website of the family of Frank and Jesse James, he says Mills approached him in March 2013 about the tintype reportedly bearing the images of Ford and James, which he found to be “blatantly false. I told her there is no way this would be a representation of either man,” James says.

In disputing Gibson’s findings, James notes the tintype she published is reversed from the image presented to him. “That’s a prime no-no in any scientific authentication,” he says. “You don’t tamper with the image.” James also says some of the photographs Gibson used as a basis of comparison are not at all authentic, including one in which the man put forth as Jesse James “displays a full set of unharmed digits” unlike the outlaw, who had a missing fingertip on an index finger. “She’s just comparing one bogus photo with another,” he says.