In the novel Sad Cypress, Inspector Brill is the police officer investigating the death of Mary Gerrard.
Inspector Brill testifies during Elinor Carlisle's trial. He is described as being "soldierly and stolid, reeling off his evidence with practised ease". He describes being summoned to the house, searching the premises, and finding a fragment of a label, such as would be used on a glass tube of morphia.