A Northglenn man was arrested after a hiker was picked up by someone she thought worked for search and rescue and sexually assaulted.

Police arrested 50-year-old William Tidwell on charges of unlawful sexual contact by force and impersonating a public servant following the July 25 incident.

The victim was hiking in the area of Caribou Road and Forest Service Road 505 in unincorporated Boulder County, outside of the town of Nederland, when she was approached by an unknown man. The man was driving what she thought to be a  “search and rescue” vehicle, a Boulder County Sheriff’s Office press release said.

The man offered to take her to a different trail. Once in the vehicle, he sexually and physically assaulted her. She was eventually able to leave and report to the sheriff’s department, the release said.

The victim described the man as wearing a green-collared shirt to appear as if a search and rescue worker. She also noted him as a bald, white male in his 50’s with a grey beard.

Investigators obtained an arrest warrant for Tidwell, a resident of the City of Northglenn, and he was officially arrested on the warrant by the Idaho Springs Police Department on Monday, the release said.

Tidwell is currently being held at the Boulder County Jail on charges of unlawful sexual contact by force, second degree assault and impersonation of a public servant, the department noted.

Detectives believe there may be additional witnesses and victims. They ask anyone with information to contact Detective Garrett Eastman with the Boulder County Sheriff’s Office at 303-441-3633 .