Medical examiner: Cheryl DeBoer died from asphyxia caused by plastic bag over her head and drowning

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MOUNTLAKE TERRACE, Wash. – Cheryl DeBoer died from asphyxia after a plastic bag was placed over her head and she drowned in freshwater, the Snohomish County Medical Examiner’s Office concluded on Monday.

DeBoer, 53, was missing for several days last month before her body was found in a culvert.

The manner of death still hasn’t been determined.

“At this point in the investigation, there is nothing to suggest DeBoer’s death was the result of an act of homicidal violence," Mountlake Terrace police chief Greg Wilson said.

Wilson said police are still waiting for the results of an examination of DeBoer's computers, cell-phone records and other evidence.

An autopsy at the time found small cuts on her fingers that appeared to be self-inflicted.

Police later found what they said appeared to be blood on the passenger seat and the inside passenger door of her Subaru, which was found about two miles away from her body.

Detectives said they ruled her husband out as a person of interest in the case.

Crime Stoppers of Puget Sound is offering a $1,000 reward for information related to this case. Call an anonymous tip into 1-800-222-TIPS.