The incident began at about 1:35 a.m. Friday when the Lewis County 911 dispatch center received a phone call from a woman who said a man had just come to her house, in the 5900 block of Highway 508 in Morton.
The man said that he and his fiance had been involved in a collision on Forest Service Road 73 and his fiance was not breathing. The man said he and his fiance had been "jumped" and he had been trying to get away when he got into a car crash on the Forest Service road.
Medics and sheriff's deputies responded to the car crash scene on the Forest Service road and found the victim dead.
The man who came to the woman's house and reported the crash is being questioned. He was identified as a 32-year-old Randle resident.
Detectives are asking the public's assistance in locating another man, Roger Etter, 39, of Kelso, who may have information related to the investigation.
Anyone with information on Etter's whereabouts is asked to call the Lewis County Sheriff's Office at 360-748-9286 or Crime Stoppers at 1-800-748-6422.
An autopsy will be scheduled for the victim.
The investigation is continuing.