Proceed With Caution

From the dustjacket:
Mr. Wedgwood was puzzled. It was odd, he thought, as he looked from his bedroom window, that someone should leave a large closed car in the middle of his front yard, but what confused him even more was the shimmering brilliance it seemed to assume as the sun rose higher. Suddenly the unpleasant truth burst upon him with a shock. It was not a car at all. It was a hearse! Jimmy Waghorn first followed the grisly  trail from the abandoned hearse to the "thing" in the tar boiler, and as luck would have it, on that same day Inspector Hanslet finally stumbled on a really substantial clue to the Patton jewel robbery. But only after Dr. Priestley made his seemingly enigmatic suggestion did it occur to either one that the two crimes could possibly be related. 

Author John Rhode with his usual ingenuity and scrupulous care has worked two apparently diverse crimes into a fascinating pattern of mystery and intrigue.