Peril at Cranbury Hall

Peril at Cranbury Hall is a 1930 detective novel by John Rhode, the pen name of the British writer Cecil Street. It marked the eighth appearance of the armchair detective Lancelot Priestley, who featured in a long-running series of novels during the Golden Age of Detective Fiction. The use of the cipher inspired a similar one used in Dorothy L. Sayers's Have His Carcase

Synopsis
An expensive new clinic is established at Cranbury Hall treating patients for fatigue with an innovative technique. Oliver Gilroy, the brother of one of the clinic's backers, is released from goal and takes over a key role at the lucrative institution. However a series of attempts of his life draw the interest of Priestley.