The Secret of Annexe 3

Blurb

The Secret of Annexe 3 is a crime novel by Colin Dexter, the seventh novel in Inspector Morse series.
The guests of Haworth Hotel rose late, after New Year's Eve. But there was one exception, the guest in Annexe 3 missed New Year's Day completely. He was still in his room, lying dead on the blood-soaked bed. Inspector Morse began investigating each of the guests. Was Mrs. Palmer really a faithful wife? Just who exactly were the Ballards? And, how had the hotel's booking confirmation been delivered to a nonexistent address?
As the novel begins, Margaret Bowman of Charlbury Drive Chipping Norton is off to a funeral. Her husband, left alone, finds an angry letter, apparently from a lover, in his wife’s handbag.
After the murder, Inspector Morse, with the help of the pretty receptionist, Miss Sarah Jonstone, examines the letters and phone messages booking the various rooms at the hotel. Discovering the non-existent address, he deduces that a postman must be involved.
Thomas Bowman, the postman, turns out to be the corpse, and his wife and her lover the instigators of the murder. Winston Grant, a black musician, was hired to provide the alibi.