Death of a Doctor — John Armour

When Dr Carleton Spence was discovered dead in his study, savagely stabbed, Inspector Bob Channing had to find a suspect. But that wasn't as easy as it should have been, because it seemed that everybody disliked Carleton Spence. Although Inspector Channing was finally able to disclose the murderer's identity, and the ingenious manner in which the doctor had been killed, he was never able to arrest his suspect.