Relative to Poison

Relative to Poison is a 1947 detective novel by E.C.R. Lorac, the pen name of the British writer Edith Caroline Rivett. It is the twenty ninth in her long-running series featuring Chief Inspector MacDonald of Scotland Yard, one of the detectives of the Golden Age of Detective Fiction who relies on standard police procedure to solve his cases.

Synopsis
A recently demobbed ATS girl is offered employment in a Regent Street café, and takes her friend along. Before long they find themselves embroiled in a case of murder