Next of Kin — George Goodchild

A millionaire dies soon after he has partaken of an evening meal. When a verdict of murder is returned, Inspector McLean finds himself confronted with a case of quite unusual complexity. One by one the suspects are eliminated until McLean is left with almost a blank sheet. He is in despair when he hits upon a small clue which causes him to follow a new line of investigation, and little by little a picture of the guilty person is built up.