“My methods? Oh, in the ordinary cases ordinary methods, and in the extraordinary cases extraordinary ones. I think there is a lot of instinct in our work. I think a man’s mind works in ways we know little of. Sub-consciously, we do a lot of real thinking.

“I have also some theories which I use; one especially.

“Every crime is a story containing a hero, often a heroine, and a large or small collection of minor characters. The story ends with the completion of the crime by the criminal hero.

“When I am called in to a really intricate case, I am like a person to whom is handed the last chapter of the romance.

“If in that chapter subordinate characters left, it is generally enough for me; one thing leads to another till the story is complete. I search for mud on boots and stains on clothes, it is true, but I plunge, if possible, into my hero’s mind and past. There lies the heart of the mystery. If there is no hero to be found, there is a heroine. I have dragged a murderer to the graveside through the mind and past of a woman.

“I did so in the Gyde case. It is true I was helped by a man called Hellier; but that has nothing to do with my theory.”

As he drove to Piccadilly he felt somewhat dissatisfied. Gyde, unable to dispose of the head of his victim, had left it behind him at the house. This showed a certain unresourcefulness in the man. Was he, after all, on the track of a common, blundering assassin?

To Freyberger the chase was everything, the feeling in the dark for another mind, and the gripping of it and the mastering of it.

A foeman worthy of his mettle, that was what he craved for and that was what he was about to find. When he arrived, the door was opened for him by a plain-clothes officer.

“Well, Jenkins,” said the detective, “what have we found?”