Grave Mistake

Another classic Ngaio Marsh novel.
At first, it looked as if Sybil Foster had intentionally left the world: with two husbands dead, a daughter marrying the wrong man and - it later appeared - a debilitating disease, it was no wonder she took her own life.
But no one believed she was the type - especially Chief Superintendent Roderick Alleyn. For the field was ripe with unfortunate engagements - one of them a very grave mistake...