And so was Janis Joplin, Billy Holiday, Jim Morrison, Jimi Hendrix, Kurt Cobain, etc., etc., etc.
Some people...fans, friends, whoever...just cannot fathom that these people were substance abusers and died as a result of their own actions. The murder suspicion always arises at some point. It is inevitable.
Every entertainer we lose too young have had questions as to death or murder. While anything is possible, the poor woman was her own worst enemy and what happened to her was inevitable unless she really changed her ways.