"I think I can guess what you did it for. It was a jolly 'cute trick of yours."
"A trick?"
"Yes," pursued Percy. "You made that drawing and invited Sharrow's criticism of it simply and solely to get him to take hold of a piece of white paper and leave his dirty finger marks on it. I believe you want to identify him with some chap who left finger-prints somewhere else. I've heard of that method of identification. It's said to be a dead sure way of telling one man from another."
"Yet I should say it is rather an uncertain method for any but experts to follow," the sergeant observed. "I shouldn't care to trust to it myself. Certainly I shouldn't venture to accuse any man of a serious crime on such flimsy evidence as a finger mark."
Rapson glanced at him curiously.
"That chap Ebenezer Sharrow doesn't look as if he could be guilty of committin' a serious crime," he ventured. "And yet I suppose you are here on his track."
"I did not say so," Silk returned sharply, reprovingly. "You appear to think that because I'm a policeman I must always be on some poor fellow's trail, hunting him down. Sharrow was personally a stranger to me until last night, when I met him for the first time in the bunkhouse."
"Then why did you go out of your way to get hold of his finger-print?" Percy insisted. "You never do anything without a reason."
Sergeant Silk did not answer him. Perhaps they were too near to the men about the drying fire for him to enter into explanations without risk of being overheard. Perhaps he had reasons for not wishing to explain.