"We'd best put it back on the rug where we found it," said the sergeant, scratching his puzzled head in his perplexity. "It will want the best brains in the force to get to the bottom of this thing. It will be a London job before it is finished." He raised the hand lamp and walked slowly round the room.
"Hullo!" he cried, excitedly, drawing the window curtain to one side. "What o'clock were those curtains drawn?"
"When the lamps were lit," said the butler. "It would be shortly after four."
"Someone had been hiding here, sure enough." He held down the light, and the marks of muddy boots were very visible in the corner. "I'm bound to say this bears out your theory, Mr. Barker. It looks as if the man got into the house after four when the curtains were drawn, and before six when the bridge was raised. He slipped into this room, because it was the first that he saw. There was no other place where he could hide, so he popped in behind this curtain. That all seems clear enough. It is likely that his main idea was to burgle the house; but Mr. Douglas chanced to come upon him, so he murdered him and escaped."
"That's how I read it," said Barker. "But, I say, aren't we wasting precious time? Couldn't we start out and scout the country before the fellow gets away?"
The sergeant considered for a moment. "There are no trains before six in the morning; so he can't get away by rail. If he goes by road with his legs all dripping, it's odds that someone will notice him. Anyhow, I can't leave here myself until I am relieved. But I think none of you should go until we see more clearly how we all stand."
The doctor had taken the lamp and was narrowly scrutinizing the body.
"What's this mark?" he asked. "Could this have any connection with the crime?"