The fairy tale that Marie was eaten by her dog comes from a song made up about the incident. And from a story in the book "Hollywood Babylon".
Miss Prevost was trying desperately to lose weight. She had virtually stopped eating and had replaced food with alcohol. Reports at the time felt she had died on January 21, 1937, but was not found until January 23. Her neighbors had complained her little dachshund had been barking and sounded in distress. When police went in they found Marie dead and her dog at her side. She had some scratches on her hand where her dog had been pulling at her, probably to try to get her attention.
So reports about the dog trying to chew on her body were ridiculously overblown.