“That is the problem which we are now about to solve,” said Sherlock Holmes.  “You remember, Inspector Martin, when the servants said that on leaving their room they were at once conscious of a smell of powder, I remarked that the point was an extremely important one?”

“Yes, sir; but I confess I did not quite follow you.”

“It suggested that at the time of the firing, the window as well as the door of the room had been open.  Otherwise the fumes of powder could not have been blown so rapidly through the house.  A draught in the room was necessary for that.  Both door and window were only open for a very short time, however.”

“How do you prove that?”

“Because the candle was not guttered.”

“Capital!” cried the inspector.  “Capital!

“Feeling sure that the window had been open at the time of the tragedy, I conceived that there might have been a third person in the affair, who stood outside this opening and fired through it.  Any shot directed at this person might hit the sash.  I looked, and there, sure enough, was the bullet mark!”

“But how came the window to be shut and fastened?”

“The woman’s first instinct would be to shut and fasten the window.  But, halloa!  What is this?”

It was a lady’s hand-bag which stood upon the study table—­a trim little handbag of crocodile-skin and silver.  Holmes opened it and turned the contents out.  There were twenty fifty-pound notes of the Bank of England, held together by an india-rubber band—­nothing else.

“This must be preserved, for it will figure in the trial,” said Holmes, as he handed the bag with its contents to the inspector.  “It is now necessary that we should try to throw some light upon this third bullet, which has clearly, from the splintering of the wood, been fired from inside the room.  I should like to see Mrs. King, the cook, again.  You said, Mrs. King, that you were awakened by a loud explosion.  When you said that, did you mean that it seemed to you to be louder than the second one?”

“Well, sir, it wakened me from my sleep, so it is hard to judge.  But it did seem very loud.”

“You don’t think that it might have been two shots fired almost at the same instant?”

“I am sure I couldn’t say, sir.”

“I believe that it was undoubtedly so.  I rather think, Inspector Martin, that we have now exhausted all that this room can teach us.  If you will kindly step round with me, we shall see what fresh evidence the garden has to offer.”

A flower-bed extended up to the study window, and we all broke into an exclamation as we approached it.  The flowers were trampled down, and the soft soil was imprinted all over with footmarks.  Large, masculine feet they were, with peculiarly long, sharp toes.  Holmes hunted about among the grass and leaves like a retriever after a wounded bird.  Then, with a cry of satisfaction, he bent forward and picked up a little brazen cylinder.