It was in March 1991, right after Scott Conway returned from the Gulf War, that he noticed the first symptoms. Extreme mood swings, anxiety, lapses of concentration and memory. The division of the United States Army with which he served, the 24th Infantry — Delta Company, First Platoon, 3rd of the 15th Battalion, motto “Can do” — had spent the last few months of the war preparing to leave, nothing too arduous, so it was only when he returned to Howard, Pennsylvania, and attempted to resume his duties as a reserve soldier that his physical ailments became clear. Road marches and exercises that should have been easy were almost impossible. He was tired all the time and suffering bouts of debilitating diarrhoea. His muscles were on over-drive some days; other days he couldn’t walk, only crawl. He experienced phantom pains all over his body. He was 20 years old.

Doctors couldn’t work out what was wrong with Conway, which meant they couldn’t give him the right medication to control his condition. But he didn’t need their diagnosis: he already knew. In early 1991, as the 24th Infantry had followed the retreating Iraqi Republican Guard towards Kuwait, it was tasked with guarding the Khamisiyah Ammunition Storage Facility in southern Iraq ahead of its planned demolition. On 4 March, the US Army blew up the 25sq km site, sending an impressive column of smoke into the sky. Among the substances released were nerve gases, most likely sarin and cyclosarin, as confirmed by the Department of Defense in 1996. The cloud from the explosion may well have drifted over Allied troops stationed several kilometres away.

A considerable number of Gulf War veterans — American, but also British, Canadian and Australian — have experienced what is now known as Gulf War Illness. Nerve agent exposure is a strongly suspected cause, though there are other possible factors, including proximity to pesticides and burning oil wells. The symptoms of the illness vary, though fatigue, memory loss and joint pain are frequently reported. To Conway, it all made perfect sense.

"If I’d known deaths were going to happen, I’d have never hid the treasure chest" – Forrest Fenn

Meanwhile, normal life was becoming impossible. He tried factory work, but it brought him to the point of exhaustion. Around 2010, he started his own construction company, but the stress exacerbated his symptoms. In early 2013, he and his wife, Traci, predicting the trajectory of his condition and wanting to travel while they still could, decided to take a Caribbean cruise. On the flight to the departure port in Florida, Scott picked up a copy of the airline’s in-flight magazine and read an article about Forrest Fenn, an eccentric millionaire art dealer who, after discovering he had cancer, filled a treasure chest with gold nuggets, jewels and ancient artefacts said to be worth between $2m and $3m and hid it somewhere in the Rocky Mountains north of his hometown of Santa Fe, New Mexico. Fenn offered nine clues to its specific whereabouts in a cryptic poem which he included in his self-published memoir, The Thrill of the Chase. “As I have gone alone in there, And with my treasures bold,” began the six-stanza poem, which the in-flight magazine had printed in full, “I can keep my secrets where, And hint of riches new and old”. Conway was intrigued.

He took the magazine home and started to mull over the clues. Soon he was browsing Google Earth, looking for lakes and canyons and rivers in the Rockies just north of Santa Fe. By his reckoning they fitted the poem’s earliest clues, which advised to, “Begin it where warm waters halt, And take it in the canyon down”. Eventually, he whittled the possible lakes down to five or six, and he came up with an idea. Why not travel to New Mexico and look for real? He invited his son, Stephen, then in his early twenties; they had had a difficult relationship and he hoped that searching for the treasure together would provide an opportunity to bond. His brother, Harry, was between jobs and around too. Conway wouldn’t be up to the physical challenge on his own, though his doctors had told him he needed to stay active. Why didn’t the three of them give it a shot?

In February 2013, they drove from Pennsylvania to Santa Fe — a two-day trip — and decided to start at the most southerly and westerly lakes on Conway’s shortlist: Heron Lake, a reservoir in New Mexico that is skirted by the Rio Chama, which feeds into another reservoir, El Vado. As soon as they arrived, Conway started to get a strong feeling. Heron Lake seemed to fit the first clue, the Rio Chama the second, and soon sites that fitted the third, the fourth, the fifth, appeared before him. Conway turned to his son: “Stephen, I’m 100 per cent positive we are on the right stream.”

Conway and his son began to walk up the stream. It grew smaller and smaller, until it was little more than a trickle, while the bank between them and the road started rising until they could no longer see over the top. No one would even know they were there. They came to a big rock, surrounded by bushes, then Conway looked to the left and saw it: a 30ft log crossed with another that had been partially burned. He knew the configuration could not have been an accident; the shape it formed was unmistakable, in fact. A giant X.

Addison Doty

In the mid-1800s, before the railroads were built, anyone who wanted to buy and sell wares in the Southwest of America and Mexico, newly opened to outside trade following the Mexican War of Independence of 1821, might well have found himself in a wagon train following the route of the Santa Fe Trail. Starting in the town of Independence, Missouri, and heading hard west and gently south across five states, the 900-mile trail was not for the fainthearted: it crossed high plains, parched deserts and came under frequent attack from Comanche Indians. In 1848, it was also one of several routes used by those crossing the country and heading to California in search of gold. A decade later, thousands more followed it as they sought their fortunes in the less well-known Gold Rush of 1859, the so-called “Rush to the Rockies”.

Today, the route of the Santa Fe Trail comes to an end at the La Fonda on the Plaza hotel in downtown Santa Fe, but a couple of miles before it does so, it passes through Forrest Fenn’s garden. It was one of the main reasons he bought the house — a large, brown complex in the soft-cornered adobe style typical of the area — back in 1988. To remind him of its history, in among the aspens, piñons, and ponderosa pines in his front yard he has placed an army ammunition wagon from 1880, the year the railroads finally reached Santa Fe and the trail fell into disuse.

The two-and-a-half acre garden is beautiful, with views over the Santa Fe ski hill, but Fenn spends much of his time in his den, which is filled up to its high ceiling with impeccably arranged Native American artefacts he has collected over his many years as an antiques dealer, gallerist and amateur archaeologist: ladies’ high-top moccasins, feather headdresses, dolls in tiny fringed buckskin dresses, and above the hearth, a row of buffalo skulls. He also collects rare books that interest him, including the annotated manuscript of A Connecticut Yankee in King Arthur’s Court by Mark Twain, an author with whom his acolytes often compare him. “You can pick up anything in here,” he instructs.

The den is where Fenn entertains his visitors. His daughter Kelly, who, like his other daughter Zoe, lives a few miles away, busies herself in the kitchen. His wife Peggy, his high school sweetheart, who is frail, is in another room in which Fenn can observe her via a video monitor on his desk. The shades are partly drawn, a fan whirrs and table lamps are lit. Nevertheless the sun outside is winning, and it is stiflingly hot. We sit side by side on a squeaky leather sofa so deep that my feet don’t reach the floor, while Fenn’s dog, Willy, an excitable poodle mix, worries the hem of my dress.

Annie Collinge

There are treasure hunts all over North America: literal manifestations of the essential national belief that if you go the distance, put in the time, make the effort — if you want it badly enough — the spoils await. There is the Lost Dutchman’s Gold Mine in the Superstition Mountains of Arizona, which is said to be stuffed with riches; there is the suitcase containing $200,000 in unmarked bills supposedly buried in 1934 by notorious gangster John Dillinger on the grounds of the Little Bohemia Lodge in Manitowish, Wisconsin, as he fled the clutches of the FBI; there is the mystery of the “money pit” of Oak Island in Nova Scotia, Canada, rumoured to be stashed with everything from the booty of 17th-century Scottish pirate Captain Kidd to the jewels of Marie Antoinette. But there aren’t many famous treasure hunts — perhaps any — in which you can still interrogate the person who did the hiding.

Fenn doesn’t invite searchers to his home anymore because of security concerns, but he is still happy to receive scores of journalists who come to find out what possessed him to set his quest. Fenn has clearly relished the attention: as well as gracing the pages of in-flight magazines he has been interviewed by newspapers, on news channels, and appeared on NBC’s Today Show seven times. He estimates that he receives around 100 emails a day from people asking for extra hints, or telling him they’re close, or even that they’ve found it. He scans them for two or three key words, which he says, “has happened three times. Three people have said key words. I never heard from them again! But they haven’t found the treasure.”

When we meet, Fenn is a few months short of his 88th birthday. He is neatly dressed, sharp as a tack, and has a manner that would be described as “flirtatious” if he were 30 years younger, but we’ll settle for “twinkling”. He is in remarkably good shape, but his age is catching up with him: he gets short of breath from time to time and is hard of hearing. (At one point I ask him what kind of cancer he had had — “Cash-deal? I don’t understand that word” — and we keep going like that until eventually I have to shout “Cancer!” into his ear at close range, which does not feel good.)

He has an anecdote for all occasions, polished to a shine, nearly all of which can also be found in The Thrill of the Chase, or his two follow-up memoirs, Too Far to Walk and Once Upon a While. But still, it’s pleasant to sit in his company and listen, his voice high and husky, as he tells them another time.

A 30ft log crossed with another, partially burned — a giant X: it could not have been an accident

There’s this one, about growing up in the Thirties in Temple, Texas: “I was sitting down on my front porch, there was nobody around, it’s a dirt road, and here comes a man riding a horse going down to the livery stable half a mile away. I’m sitting there all by myself, eight or nine years old, and I say, ‘Hiya, cowboy!’ Well, he got off his horse and came over and hit me on the jaw just as hard as he could, knocked me down, broke my lip, got on his horse and rode away. I made my first rule: don’t make the alligator mad until you’ve crossed the river.”

Or this one, about hijinks in high school: “Five of us were at the Belton Bridge one time, about eight miles from Temple, and we were going to jump into the Leon River. Just before we jumped, one of the guys said, ‘If you hit a log that’s floating just under the surface you can break both your legs.’ I didn’t jump. But it started really bothering me. About a week later, I jumped in my 1935 Plymouth car, about one or two o’clock in the morning on a cold winter night, and drove out to the Belton Bridge all by myself. It was so dark I couldn’t see the water, but I knew it was there. I jumped into the water with all my clothes on and my shoes and everything. I hit the water with a hard bang, but when I surfaced I was a whole different person.”

Or this, about his military career: “I made terrible grades. My father was a principal, so I think that’s why I graduated, but then when the Korean War came along I joined the air force in order to keep from getting drafted in the army. I became a fighter pilot and an officer and everything changed. I got to Germany in 1957, I was 27 years old, and they took me down to Supply and I signed a requisition for an atomic bomb. I owned that atomic bomb. So that’s what they gave this kid with no education who didn’t know very much. They give you authority and responsibility and they expect you to rise to it. And I did.”

Fenn went on to fly 328 combat missions in the Vietnam War — he was shot down twice — and was awarded various medals including a Silver Star, three Distinguished Flying Crosses, and a Purple Heart. After retiring from the air force as a major in 1972, he, his wife and daughters moved from Lubbock, Texas, to Santa Fe. They set up Fenn Galleries, which traded in southwestern art from the likes of Georgia O’Keeffe and the landscape artist Eric Sloane. Fenn chose art, he says, because, “I wanted to be in the kind of business where my worst customer gave me $3,000.” As well as art, Fenn Galleries was known for the menagerie of animals Fenn kept there, including a scarlet macaw, donkeys, raccoons and a pair of alligators called Elvis and Beowulf who swam in the lake he built in the backyard. I ask why he had so many unusual animals. “PR,” he says.

Whatever his promotional wiles — he also extols the virtues of “full-page colour advertising” — it worked, and all kinds of customers stepped through his doors, from Cary Grant and Steven Spielberg to David Rockefeller and Jackie Kennedy. One of his favoured routines is to present the bottle of brandy purportedly left behind by Kennedy after her stay at his guest house and to ask you to close your eyes and imagine her as you take a sip. As I took the bottle, its contents miraculously undiminished, I couldn’t help thinking of all the other journalists whose mouths had been on it, or of the burly bodyguard whose bottle, for all I know, it may well have been in the first place.

Annie Collinge

In 1988, Fenn’s doctors discovered a large tumour under his right kidney and gave him a 20 per cent chance of survival. He sold the gallery the same year. It was then that the treasure hunt idea came to him. The exact wording has morphed a little over the years, but involves a conversation with the fashion designer Ralph Lauren, who’d come to his house and wanted to buy a headdress from him. After being refused, Lauren reportedly told Fenn, “You can’t take it with you,” to which Fenn immediately replied, “Then I’m not going to go!” But later that night he had a different thought: “Who says I can’t?”

The plan he devised was dramatic, and not a little gothic. He bought a small bronze chest, five inches high and 10 inches wide, which he gradually filled with small, high-value items including gold nuggets and coins, jade figurines, antique jewellery, rubies, emeralds, sapphires and diamonds. When death was close, he would take the chest to a secret location he had already decided upon, which he would describe in a poem of cryptic clues. There, he would swallow 50 sleeping pills, just as his father, Marvin, suffering from pancreatic cancer, had done a year earlier.

“The alternative is a hospital bed, with tubes down your throat and needles down your arm, friends and relatives standing around holding your hand, crying. Is that what you want?” says Fenn. “They put you in a deep hole and cover you up, it’s dark down there, it’s damp, it’s cold, you can’t see out… If I’ve got two days to live, take me out under a tall pine tree way out in the forest, leave me a bottle of water, and go on back to town. I don’t need you anymore. That’s what the old Indians used to do, the people who couldn’t travel. They left them by the trail there.”

Anyone who solved the clues would find not only the treasure, but Fenn’s own sun-bleached bones. Except, of course, Fenn didn’t die, he recovered, and it wasn’t until he was approaching 80 that he finally got around to venturing out with his treasure chest — into which he also placed a few of his own hairs (“so that in 1,000 years, when that thing is found, they can do a carbon-14 test”) and an abridged version of his autobiography, printed in tiny type and sealed in a bronze jar — and hiding it in the secret place for which he had so long intended it.

There are treasure hunts all over North America: if you want it badly enough, the spoils await

His main motive, he has said many times since, was to address today’s “sedentary society” and “get kids out of the game room”. It was also, he has pointed out, during the aftermath of the 2008 financial crash. “We were going into a depression, lots of people were losing their jobs. I wanted to give some people hope.” As for whom he wanted to inspire, he says: “Every redneck in Texas that lost his job, has 12 kids and a pick-up truck and a sleeping bag. Throw all those things in the back of your pick-up truck. That’s who I hope finds the treasure chest. Somebody that can use it.”

He published The Thrill of the Chase in 2010. It didn’t take long for people to notice. “I printed 1,000 copies because I thought, ‘My parents are dead, who’s going to buy my book?’ And two or three weeks later, it went into reprint. It’s now going into its 11th printing.” Fenn gave permission to an independent Santa Fe bookstore called Collected Works to oversee new print-runs at its own cost and to keep all the profit bar a small percentage which Fenn distributes to cancer sufferers. It remains the only retailer from which the book is available. According to Fenn, it has now sold 40,200 copies. (In an email, Dorothy Massey, the store’s owner, confirms sales are “in the thousands” and that the arrangement has “obviously made a great impact on Collected Works Bookstore and its financial health”.)

It’s not clear how many people have gone searching for the Fenn Treasure. Many of them congregate on online forums or the comment sections of dedicated blogs and YouTube channels, where they swap theories and photographs and, in many instances, insult each other. Others, like Scott Conway, do their research alone. Fenn estimates that 350,000 have gone looking — something of an increase on the figure of 1,000 he gave the in-flight magazine in 2013 — and has lost count of how many emails he has received from unsuccessful searchers who have found a greater treasure: time together as a family, a love of the great outdoors, a new sense of purpose.

There are also plenty of people who say the Fenn Treasure is an ego-trip, a marketing ploy, a refusal to accept the anonymity that ultimately comes to us all. Or a hoax. I feel duty-bound, as every interviewer does, to ask him the obvious question, to which he feigns outrage. “Is it really there? If you’ve read my book and would ask me that question I may punch you right in the nose like that cowboy.”

Annie Collinge

And then there are the deaths. In January 2016, 54-year-old Randy Bilyeu disappeared while looking for the treasure in northern New Mexico. Seven months later, his remains were found by the side of the Rio Grande; his cause of death could not be ascertained. On 9 June 2017, the body of 53-year-old Jeff Murphy, who’d told his wife he was going in search of the Fenn Treasure, was discovered at Turkey Pen Peak on the Montana-Wyoming border. It was concluded he’d lost his footing and fallen 500ft to his death. Nine days later, on 18 June, the body of 52-year-old pastor Paris Wallace was found in the Rio Grande. He had been searching in New Mexico, and it appeared he’d been attempting to cross a tributary of the river using a rope that had given way. Ten days after that, 31-year-old Eric Ashby disappeared while rafting along the Arkansas River, reportedly also in search of the treasure. His body was discovered a month later.

After the death of Wallace, New Mexico’s State Police Chief, Pete Kassetas, told Good Morning America: “I want Mr Fenn to retrieve the treasure or call off the hunt after he retrieves the treasure.” The TV news item also included an interview with Wallace’s widow, Mitzi, a fellow searcher, who said of the quest: “It was a great way for us to get out in nature, to have some quality time together; it was an escape for us.”

Fenn is used to being asked about it, and has a ready response: “It’s tragic and I feel terrible that it happened, but you know that nine people die in the Grand Canyon every year? They run out of water, they fall off the mountain. When you got on an airplane in England to come to Santa Fe, New Mexico, you stuck your neck out. There are no guarantees in life and everybody’s responsible for their own actions. But if I’d known that was going to happen, I’d have never hid the treasure chest.”

He has given certain further hints over the years, to stop searchers from taking unnecessary risks. The chest is not in a mine. It is not higher than 10,200ft above sea level. It is not in a cemetery, nor an outhouse (clarifications he gave after two diggers reportedly came up with very different interpretations of the clue “Put in below the home of Brown”). He has also reminded searchers the chest was hidden by an octogenarian.

One thing he hasn’t done is call it off. “The State Police Chief told me to shut it down and my comment was, ‘You have to listen to the State Police Chief,’ but, of course, I never did shut it down either,” he says. “I can’t go back and get it, and I will never tell anybody else where it is. The treasure chest belongs to destiny. It’s part of history. And in my view, there have been so many people looking for it I don’t have the right to shut it down. But I’ve told myself if somebody’s murdered because of the treasure, then I’ll shut it down. That’s going too far.”

Then he turns to me, with an amused expression. “You saved that question for the last one.” Not quite, I say, but yes. “You’re so funny. You’re like all the other writers. They want to get the story before they make me mad.”

And does it? I ask. Make him mad? “No, but potentially it would. That’s why I say I don’t dwell on it. It’s tragic, and I’m sorry, but that’s all you’re going to get out of me. But like I said, if I’d known that was going to happen, if I’d known one person was going to die, of course I wouldn’t have hidden it.”

As we wind up the interview, he points at my notebook. “What if I stole that from you? And that,” he says, pointing at my Dictaphone. “You’d lose your job, wouldn’t you?” I tell him if he did that I’d have to punch him in the nose right back. Which doesn’t feel too good, either.

As we say goodbye, he gives me a miniature can of Dr Pepper for the road, and requests a peck on the cheek. We make the trade.

despite the discovery of the x, the Fenn Treasure did not reveal itself to Scott Conway as easily as he was expecting. In fact, he revisited the site a further 16 or so times, bringing along different friends and family members to help him, all of whom were promised a share of the bounty when it was eventually found. They dug down and out, through frost a foot-and-a-half thick and, as they got deeper, freezing ground water that rose up. The site became known to those involved as “The Hole”.

Even Conway’s wife Traci joined him on one trip, though it was a miserable experience. The spot in which they were digging was in a state park and she was terrified of getting caught. But to Conway it seemed apt that the treasure be in an area that might have legal ramifications for excavation, as hinted at by references in the poem to “no place for the meek” and needing to be “brave”. What could be braver, and more in the spirit of Forrest Fenn, than ignoring the diktats of petty bureaucracy? Nevertheless, the expeditions were taking their toll. On occasion, Conway grew so tired from digging he had to be dragged out of the hole by his companions. But his metal detector was indicating something very nearby. He knew he was getting close.

Treasure hunter Scott Conway standing in ’The Hole’ which he says took 400 hours to dig and which has so far cost him over $30,000 Annie Collinge

Then during a trip in May of this year, Conway came out with two new friends. One night, an argument broke out about who was and wasn’t pulling their weight. One of them chose not to turn up to the site the next day, but a couple of hours later, some park rangers did, armed with M16s. As far as Conway was concerned, it was no coincidence. The rangers confiscated Conway’s metal detector and tools, forbade him from digging further and told him to expect notification of a court date. He did not know what his punishment might be: the law varies depending on who owns and operates the land, be it a private owner, state or national park services, or the Bureau of Land Management, and sentences can range from fines to imprisonment. For Conway, the hunt was over when he was closer than he’d ever been. Traci’s worst fears had come true. But there was another person he needed to tell.

On 23 June 2018, the Collected Works bookstore in downtown Santa Fe hosted a book signing with Forrest Fenn. Fifty or so people attended, many of them in town for Fennboree, a gathering of searchers — or Fenners, as they sometimes call themselves — which has happened every year since 2014. Fenn sat at a table at the back of the store and people came up alone or in family groups to show him photos on their phones, or to request cryptic inscriptions, or to thank him. As they wrote their names on a separate piece of paper to ensure Fenn spelled them correctly, the hands of many of them were shaking.

Halfway through the signing, Scott Conway approached the table. He made little conversation as Fenn signed his book, then he passed him a handwritten note. Fenn read the paper, then looked back at Conway.

“You’re going to jail, you know that,” said Fenn.

“I know it,” said Conway, grimly. “We’ll be there together.”

“Maybe we could play canasta together?” offered Fenn, but Conway did not crack a smile.

Local handyman Anthony Scott Richards is not an active hoard hunter but volunteered in the search party to look for 54-year-old Randy Bilyeu, lost in the Rocky Mountain wilderness while attempting to unearth the Fenn Treasure Annie Collinge

It’s on the day after the book signing that Conway tells me his story. I had seen him at the bookstore, and met him the previous night at the Fennboree opening soirée in a conference room at the Hyatt Place Santa Fe where there was Frito pie and a quiz (sample question: What is Forrest Fenn’s favourite soda? Answer: Grapette). Conway is 47 now, a little heavy-set, and has dark eyes that you might imagine have seen some things even before you know that they have. He seemed anxious to talk more and said he had something to show me, which is how, on this particular morning, we come to be heading north out of Santa Fe on Route 84 towards the foothills of the Rocky mountains.

Anthony Scott Richards, a 48-year-old widower from nearby Jemez who works as a handy-

man, has come too. He has a wispy beard and a kind face and knows the mountains well. He isn’t actively searching, he says, but was one of those who volunteered to look for Randy Bilyeu. He remembers he found gloves and saw a set of footprints going straight down the side of a canyon, but was dissuaded from looking further by the official search and rescue teams. “And he was right there,” says Richards. “He would have been found a little sooner.” Now he accompanies searchers if they ask him, to help them remain safe. He often carries his 9mm pistol or his .357 Magnum revolver, in case of bears.

I ask Conway what I should expect to see. “You’re going to see ‘where warm water halts’, you’re going to see ‘in the canyon down’, I’m going to show you ‘no paddle up your creek’ and I’m going to show you where ‘the blaze’ was,” he says, making various references to the poem’s clues. “And I’m going to show you the hole I dug. And I’m going to show you where the treasure is.”

Conway is adamant he’s on the brink of discovery: ‘Without a shadow of a doubt I’m four feet away’

As we drive he explains, in exhaustive detail, his solution for each clue, and then, as we draw nearer, he gives instructions of where to pull over to see each one. Here, from an overlook at the Heron Dam, we see where the opaque water of the Rio Chama meets the colder, darker water of Willow Creek: “where warm waters halt”. Further on is a concrete ramp into the river to launch, or “put in”, boats “below the home of Brown”: the Rio Chama is known for brown trout. As Conway explains each one he gets visibly more excited. It is infectious.

He talks about some of the good moments he’s had on his search. About the family of chipmunks that moved into the hole for a while, about the wild turkeys that occasionally appear over the verge, and about the sense of himself that it has brought back to him. “Before I was in the war, I was adventurous, I was energetic; then after that war, that was all gone. It just seemed that that part of me had died and I didn’t realise it,” he says. “It gave me a rebirth.”

Recently, those feelings have given way to something else. “If you ask me what this is for me right now, it’s a burden,” he says. He estimates he’s spent more than 400 hours digging, and $30,000 of his own money. (As of July, he will have added another $329 for the fine he receives for metal detecting in a state park, littering and “unlawfully mutilating or destroying a sign, guidepost or work.”) So why does he persevere? “Because there’s a chest that needs pulling out of the ground so that people quit dying,” he says.

Then we’re out of the car and walking along a small winding stream, with a grassy verge to our right, and all of a sudden around the corner, there it is: The Hole. It is 12ft deep, perhaps 20ft across. A very big hole. It had been bigger, Conway explained: 14ft deep and 30ft wide, but a mudslide had filled some of it back in. He gives me a tour, showing the different textures of rock, the large stones he’s moved, the remnants of the X made of logs, the place where the metal detector “went crazy, kind of what you expect to hear at a casino when you hit the jackpot”.

He sees Fenn’s handiwork everywhere. In the “puzzle” of rocks that had to be taken out in a certain order, in the curve of the stream which “Forrest had pushed out”. The very idea an 80-year-old man might have dug this deep is incredible. “Your average 80-year-old? No,” says Conway. “But Forrest, and his ability at that point? I’d probably say yes.”

As Conway talks he reveals his full vision, which is far more macabre even than Fenn’s. It involves Fenn as a younger man discovering a buried skeleton, perhaps a mountain man caught in a mudslide, whom Conway refers to as “Dead Man Jones”. This is what Conway believes Fenn was referring to when he wrote in The Thrill of the Chase; “Two people can keep a secret if one of them is dead.” According to Conway, cavities in the earth reveal that Fenn retrieved artefacts from the site, perhaps a gunpowder horn and a muzzle loader, and then, years later, buried his chest in a sepulchre made out of stones, alongside the dead man.

He hopes that when he explains his story to the authorities, they will arrange for archaeologists to come to the site and excavate the treasure, ending the search once and for all. Like Mark Twain, like Forrest Fenn, Conway has a book in him he thinks, to add to the echo chamber of narratives of free-spirited American individualism. It will be called Chasing Fenn and Finding Jones. He hopes he may be able to use his fame to raise awareness of Gulf War Illness, which he feels the US Government has neglected to do. It’s a stance with which Anthony Scott Richards is sympathetic. “When our government buries something,” says Richards, “it’s gone.”

Conway is adamant he’s on the brink of discovery: “Without a shadow of a doubt I’m four feet away.” It’s ludicrous and far-fetched but also dark and exciting and I find myself wanting it to be true. As Conway turns away, I ask Richards what he thinks. Softly, he shakes his head.

At a nearby restaurant after the signing at the Collected Works bookstore, Forrest Fenn orders a lunch of prickly pear ice tea and fish and chips. He seems glad to have made his escape. “Being Forrest Fenn is very difficult,” he says; he acknowledges that “there’s a lot of good people,” but their interest in him can be overwhelming. “You have to be nice to them. A lot of times I can’t get away from them. They never stop talking and you can’t just turn around and walk away.” There have been incidents at previous public appearances where people got angry. “There aren’t very many of them, but there are some that are mentally disturbed to some degree, or they’re mad because I won’t tell them where the treasure is. You can see what I go through every day.”

Another story Fenn recounts is about a call he once took on his home telephone. The male voice on the line told him he had found the treasure; Fenn replied he would have to go out and check the spot to see if that were true. As he left his house he noticed a black limousine pull out behind him. The week we meet, he has just received a letter from a man saying he knows where the treasure is and demanding an audience. The man had written he would be coming to his house the following Tuesday, at 1.30pm. Fenn plans not to open the gate.

Annie Collinge

I ask Fenn whether he enjoys the fact his quest has brought him into so many people’s lives, and them into his. “That’s not a plus for me. It was fun for a while, but eight years of 100 emails a day?” The content of the messages, too, can be intense. “I get an awful lot about religion in my email,” he says. “Because they believe in Jesus and God they must be a really good person so I should give them a clue. And half of the other people are sick, or their mother’s sick, or their sister’s in a coma, or on and on…” A moment later, he checks himself: “I have to be real careful not to get callous about it. I have to keep reminding myself I asked for this.”

When he was younger, Fenn used to like to lie on his back beneath a tall pine tree and look straight up. “You cannot imagine how that’ll change your temperament,” he says. An irony of his treasure hunt is that despite his aim of getting people out into nature, it has contributed to his own movements becoming more circumscribed.

These days, his doctor wants him not to sit at his computer reading emails for too long, so he takes Willy for walks around the garden. He has placed five or six chairs at different vantage points. Next to some of them, he has placed a bottle of water. He likes to smell the breeze come in, and observes little things happen. Sometimes he’ll turn on the hose and water one of his trees: a cottonwood, or a Russian olive or Siberian elm. “I like to think I’m doing something worthwhile,” he says.

He sits by the side of the Santa Fe Trail and he waits.

Photographs by Annie Collinge