Cloud, the Smiter by Arthur Gask

Three days later the detective was again closeted with Inspector Romilly in his room. The latter looked worried and his handsome face was drawn up into a puzzled frown.

"Well, Jackson," he said grimly, "I've read your precious report and if you stop fidgeting with your feet I'll read it over again. I've read it a dozen times already, but I want to read it again as if I'd never read it before. An idea that came to me the very first time that I read it has developed now almost into a certainty. I'll read it out and we'll see how it strikes you."