TELLURIDE, Colo. — The San Miguel County Sheriff’s Office announced Thursday evening that the search for missing hiker Tim Cannon has been discontinued.

Cannon, 55, was last seen by his wife after reportedly going hiking on Sunday, according to the Telluride Daily Planet.

Since then, deputies and volunteers (both from the community and search-and-rescue teams) had been searching for Cannon in the Iron Mountain area near Telluride.

The Army National Guard and Century Link provided assistance with helicopters. Additionally, three K-9 teams from Dolores joined the search, according to the sheriff’s office.

“After four days of an aggressive and extensive air and ground search utilizing the best resources available and thousands of manpower hours, I am confident we did our best to find Mr. Cannon,” San Miguel County Sheriff Bill Masters said in a Facebook post.

“The safety of our teams is always a priority, and the longer this search continues in this treacherous terrain, the risk of injury to these volunteers increases. This is not the outcome we all hoped for.”

Masters also thanked everyone who helped in the search effort. He said he would re-evaluate the decision should credible evidence in the case become available.

The search is separate from one for a man missing in Rocky Mountain National Park.