He did something, too, as you say, in America, to cover up his tracks.

Very well.

By the keen detective these actions are easily traced.

I shall at once place twenty-seven of the best men I know on the track of those twenty-seven persons." "I call that shadowing with a vengeance," remarked the Chicago man.
"It will be very easy.

The one who has committed the crime is certain, when he is alone in his own room, to say something, or to do something, that will show my detective that he is the criminal.