The Midnight Hour by Elly Griffiths

In this mystery set in Brighton, England, in 1965, private detective Emma Holmes investigates the murder of a theatrical impresario. His wife, a former music hall star, is accused of killing him. To prove her innocence, she hires Emma and her partner in the firm, Samantha "Sam" Collins, to solve the crime. Emma is also the wife of the police superintendent, Edgar Stephens, and they decide to work together, along with a young police officer, Meg Connolly. Griffiths writes vividly...