Title: The Muzzle - Minette Walters - book
Summary :
Mathilda Gillespie talked too much, drank too much, and terrorized those around her. She was extremely rich, greedy, and a liar. Her daughter took drugs, her granddaughter stole from her. Her will, ignored by all, disinherited them. She was found drowned in her bathtub, garlanded with asters and white nettles, like Ophelia, and wearing a rusty iron muzzle, like a medieval witch. This suicide, or more likely this murder, was a kind of masterpiece, an enigma resulting from a lifetime of lies, strange loves, hatreds, and violence. Perhaps only Mathilda's diary could reveal all its secrets. But this diary has disappeared.