APACHE JUNCTION, Ariz. — At 8 a.m. July 6, Curtis Merworth drove his wife, Emma, to her job as a motel housekeeper in downtown Salt Lake City, picked up two friends and headed south. In the early evening, he parked his Saturn at a trailhead on the edge of the Superstition Mountains Wilderness Area 40 miles east of Phoenix. The three men presumably slept in the car.

Next morning, they hiked into the scorched, forbidding mountains in search of the fabled Lost Dutchman Gold Mine.

Then they vanished.

On July 11, Curtis' son, Leroy, called authorities to say the men — Merworth, Andean Charles and Malcolm Meeks — were two days late coming home. Sheriff's deputies found the empty car, and at 2 p.m. a search that eventually became massive was launched.

It went on for a week, involving 96 square miles, helicopters and fixed-wing aircraft (one with thermal detection), bloodhounds, 45 searchers on horseback and 311 on the ground. (Vehicles could not be used; they are prohibited in federal wilderness areas).

Not a trace of the three men was found. The search was officially suspended at noon July 18. It is unofficially continued on weekends by the private Superstition Search and Rescue organization.

The mystery of what happened to the men begins with the mystery of the Lost Dutchman Gold Mine. It is a tangled story, part fact, part fiction, but essentially this: In the 1870s, a German immigrant named Jacob Waltz (there are various spellings of his name) came out of the Superstitions with a tale of an astonishing gold strike — enough, he supposedly bragged, to produce 20 millionaires. Before he could pack train a fortune in ore, Waltz died, reportedly of pneumonia, in 1891, without ever telling anyone where that rich, secret vein was located.

The search for the mine — called Lost Dutchman because the German-born Waltz was known to other prospectors as "Deutsche" — has been going on for nearly 120 years. During these years, it has also been the subject of books, movies, board games and songs. Popular culture aside, it is a dangerous place, and not just because of the steep canyons hidden by brush. Treasure hunters have been shot at by rivals, and some have been killed. (Years ago, in stories for LIFE magazine, I went into the mountains with two of the hundreds of unsuccessful prospectors. We all carried pistols).

The most famous victim was an amateur explorer named Adolph Ruth, who disappeared in the mountains in the summer of 1931. Six months later, his skull was found — with a bullet hole in it. That highly-publicized murder insured the mine's impact on history and its irresistible attraction to those afflicted with "gold fever."

Curtis Merworth was one of them. As a boy, he read stories about prospecting, and interest turned to obsession. Park maintenance was his job; gold was his dream. He had searched for the mine twice before, and last year he wandered off trail and got so lost, he had to call on his cell phone for help. In July he left his phone at home, probably because his trip was brief and mobile service is quite uncertain in most of the area.

But he had a new map, and he told family members he was optimistic. "We were all excited," his mother, Carol, remembers.

The two friends he took with him were dubious choices for such a physically demanding mission, however. Andean Charles, 66, a retired coal miner, had glaucoma, and Malcolm Meeks, 51, a construction worker, took medication for heart trouble.

The area where the mine is thought to be is a half-day's hike from where Curtis parked his car, which could mean the men planned to camp out at least one night. But their families do not recall them taking camping equipment, nor an adequate supply of water.

The mountain-savvy officials who guided the search for the men are baffled by their behavior, especially Curtis'. "He was missing there last year and should have realized the dangers," said Maricopa County Sheriff Joe Arpaio, whose office was in charge of the search.

Some authorities wondered if the men went into the wilderness at all — or just parked the car (which one official described as "a piece of crap") and took off on an adventure they wanted to keep from their families. But as the weeks passed, that seemed increasingly unlikely.

What really happened? Arpaio's chief deputy, Larry Black, speculates: "Someone got injured, twisted his ankle, something like that. They split up. Or darkness came, and they got lost." Besides the cliffs and canyons, there are uncovered mine shafts dug by prospectors in the past.

"The whole thing is exposure and water," Black says. "The temperature was 115. And there really isn't any water back there, not at that time of year."

When the search was called off, Arpaio was sympathetic toward the men's families. "They should not give up hope," he counseled. "There's always that one chance."

Today he is realistic. "If they're in there, we should find the bodies in November" which brings cooler temperatures and an influx of tourists, he said. "That's when the hikers come back."

It will be a gruesome discovery. What will the weather and predators leave? "Bones," says Arpaio, "and they probably will not be in one piece. But we'll be able to identify them with DNA."

Richard B. Stolley is senior editorial adviser at Time Inc. and a Santa Fe resident.