The Plaintive Numbers — Gavin MacDonald

A financier, who is proposing to write his autobiography, is found murdered with a visiting card in his hand. Sergeant Alistair MacRae is astounded when Chief Inspector Ian Forsyth is able to deduce that the hand had originally held a playing card and is able to name the people who placed the cards in the hand. Suspicion for the murder falls on the financier's four university friends, now respectable citizens, whose careers would be blighted if revelations of youthful indiscretions were now revealed. When an attempt is made to steal what exists of the manuscript, Forsyth and MacRae are convinced that the son of the financier knows more about the crime than he is confessing. When the son is murdered in a room where the window is securely fastened and the door under the surveillance of a policeman, all MacRae and the rest of the squad can come up with is that the policeman was bribed. But Forsyth, by the use of logical deduction, is able to arrive at a solution that explains the impossible crime.