Authorities suspended the search Monday for three Utah men reported missing while looking for the legendary Lost Dutchman Gold Mine in the rugged Arizona wilderness.
Maricopa County Sheriff's officials said more than 350 deputies and volunteers covered almost 100 square miles in seven days of searching for the three hikers from Salt Lake City.
Helicopters, search dogs, searchers on horseback, and a plane with thermal-imaging equipment were also used to scour the Superstition Mountains about 40 miles east of Phoenix.
"We are the leading search and rescue agency in the state, and our experience is leading us to believe that these men succumbed to the summer heat," said Sheriff Joe Arpaio. "However, we must consider all possibilities and that they could be alive and located somewhere other than the Superstition Mountains."
Family members said Curtis Meriworth, 67, Ardean Charles, 62, and Malcolm Meeks, 51, left Utah on July 6 and planned to return home by July 10. The men reportedly planned to hike into the mountains and explore the area during the day and spend nights in a motel.
Deputies found their vehicle parked at a trailhead July 11 after the men's families reported them overdue.
Arpaio said the men reportedly entered the wilderness with little water and camping equipment. Two of the men were said to have medical conditions.
The area near Lost Dutchman State Park and the Superstition Wilderness is filled with steep canyons, soaring rocky outcroppings, cactus and heavy brush. Daytime temperatures have been in the triple digits for weeks.
Treasure hunters have been looking for the Lost Dutchman mine for more than a century.