"I am positive. But be careful, or he will get away."
"He won't get away from me," said the policeman.
Nick Smithers was hurrying for the street when Nat and the officer of the law came up to him.
"Stop, Nick Smithers!" cried our hero, and caught him by the arm.
The swindler swung around, stared at Nat, and his face fell.
"This is the time you don't get away so easily," went on Nat. "Officer, do your duty."
"You'll have to consider yourself under arrest," said the policeman. "This young man makes a charge against you."
"Why, that young man is a lunatic!" cried Nick Smithers, thinking of his experience on the train. "They let him out of the asylum only day before yesterday."
"Don't you believe a word of it," said Nat. "This rascal is one of the slickest swindlers in the world. Take him to headquarters, and I'll go along and prove every word I say."
"You'll have to come along," said the officer.