I'm not presenting it as a "conclusion" though which would be a final determination, and I never used that word, you did. I said: it has "become clear to LE".
When a suspicious death investigation begins, they must be open to homicide, suicide and accidental. They appear to have narrowed it down (i.e. it has become clear to LE) that there is no (zero!) evidence to support homicidal violence, and I assume they've also ruled out accidental.
Under Washington RCW's, LE don't decide the manner of death, they need to present the evidence to the ME who will make a determination. This is why they have not yet made a definitive statement, because they don't make the decision/ruling.
http://www.seattletimes.com/seattle...ed-of-drowning-had-plastic-bag-over-her-head/
At this point in the investigation, there is nothing to suggest DeBoers death was the result of an act of homicidal violence, Police Chief Greg Wilson said in the statement."
https://www.facebook.com/DavidRoseQ1...75428069147003
"
My colleague, Brandi Kruse, talked with Mountlake Terrace Police Chief Greg Wilson this morning to get some clarification on the lack of evidence to suggest a homicide in Cheryl DeBoer's case. He says there were no defensive wounds. Her car was locked and secured. Her clothes were intact and not disheveled. No tips have come in that offer any insight into her death that would suggest it was a homicide. No physical evidence or lack of evidence that would support robbery, assault, or abduction. There is no evidence she was restrained. You have to put emotions aside. Thats difficult for the community. Its difficult for the family," said Chief Wilson who added As with any case like this, were going to take a methodical approach in our investigation." Several crime labs are assisting in analyzing evidence including the plastic bag, her car, computer and phone records. The Chief says it would be premature to rule on manner of death before those labs are done analyzing that evidence."