He was anxious to know what theory his superior officer had formed.

"And how do you fit in the letter advising us of the murder?" asked the
inspector.

He produced the letter from his pocket-book and looked at it earnestly.

"There were two of them in it--one a savage ruffian who will stick at
nothing, and the other a chicken-hearted specimen. They often work in
pairs like that."

"So your theory is that one of the two shot him, and the other was so
unnerved that he sent us the letter and put us on the track to save his
own neck?"

"Something like that."

"It is not impossible," was the senior officer's comment. "Mind you, I
don't say it is my theory. In fact, I am in no hurry to form one. I
believe in going carefully over the whole ground first, collecting all
the clues and then selecting the right one."

Rolfe admitted that his chief's way of setting to work to solve a
mystery was an ideal one, but he made the reservation that it was a
difficult one to put into operation. He was convinced that the only way
of finding the right clue was to follow up every one until it was proved
to be a wrong one.

Inspector Chippenfield continued his study of the mysterious message
which had been sent to Scotland Yard. It was written on a sheet of paper