"That is so! Mr. Douglas went round the house every night the
last thing before he turned in to see that the lights were right.
That brought him in here. The man was waiting and shot him.
Then he got away through the window and left his gun behind him.
That's how I read it; for nothing else will fit the facts."

The sergeant picked up a card which lay beside the dead man on
the floor. The initials V.V. and under them the number 341 were
rudely scrawled in ink upon it.

"What's this?" he asked, holding it up.

Barker looked at it with curiosity. "I never noticed it before,"
he said. "The murderer must have left it behind him."

"V.V.--341. I can make no sense of that."

The sergeant kept turning it over in his big fingers. "What's
V.V.? Somebody's initials, maybe. What have you got there, Dr.
Wood?"

It was a good-sized hammer which had been lying on the rug in
front of the fireplace--a substantial, workmanlike hammer. Cecil
Barker pointed to a box of brass-headed nails upon the
mantelpiece.

"Mr. Douglas was altering the pictures yesterday," he said. "I
saw him myself, standing upon that chair and fixing the big
picture above it. That accounts for the hammer."