I've sung the praises of Leo Bruce's Sergeant Beef stories before on this blog, and Cold Blood, the eighth and last novel in the series, is a good example of the traditional mystery. The book was published in 1952, and is darker and less exuberant in tone than the early novels in the series, but there are still several good jokes, not least the references to famous fictional detectives.
As usual, the story is narrated by the pompous Lionel Townsend, the most snobbish of Watsons. The Beef-Townsend relationship has a distinct flavour and is one of the great pleasures of the series. At this point in his career, Beef is a private investigator, having left the police, with whom he remains on pretty good terms. This is a country house mystery, and Golden Age tropes abound.
Beef is called in by a friend of the late Cosmo Ducrow, who has been found with his head bashed in, presumably by a croquet mallet. Ducrow was a wealthy man, and one of those who stood to inherit, his nephew, is the prime suspect. But those close to the nephew believe he is innocent, and curiously, despite the evidence against him, he has not been arrested.
The plot is very nicely structured, and it certainly kept me guessing. Kate Jackson has also expressed her enthusiasm for the novel in her splendid blog. I'd be interested to know why Bruce decided to abandon Beef in favour of Carolus Deene, who featured in a long series but has never attracted quite as much enthusiasm. One possibility is that, after a spell in prison for alleged sexual offences (a conviction that now has the strong whiff of a miscarriage of justice) he decided to break with the past.