Absolutely police would share their theory with family. At the same time, police released to media that they were dealing with "sensitive information" that required toxicology and electronic device examination for confirmation.
Toxicology and electronic device examination did not confirm that "sensitive" belief that Cheryl committed suicide. In fact, it left the only evidence in support of suicide as: plastic bag on head, 6 days in creek, fully clothed, and unknown book in car.
If police presented their suicide theory to the family, the family could very well still question that theory. Why wouldn't they given the animal blood, the claustrophobia, the day to day activity, and the bizarre theory of
death by holding breath in hip deep, cold water drainage ditch?
Police don't have "sensitive information that explained suicide", the fact that they believe it is a suicide, and that she was found face down in a shallow creek with a fast-food restaurant plastic bag on her head", is sensitive. When the family revealed that "sensitive information" on a discussion forum, police released the full spectrum of the sensitive information:
http://mltnews.com/mlt-police-chief-shares-some-details-of-cheryl-deboer-investigation/