In Strollo’s pocket Petrosino found a letter to the brother _from_ Tony Torsielli, the murdered man. It was in Strollo’s own handwriting and enclosed in an envelope _addressed to Torsielli himself_ at Lambertville. This envelope bore a red two-cent stamp. On the basis of this letter, aided by Strollo’s contradictory statements, Petrosino reconstructed the murder and demonstrated that there _was_ no brother, that Strollo had _invented_ him for the purpose of luring Torsielli to New York, and that he had acted as amanuensis for Torsielli and carried on the correspondence for both. The envelope addressed in Strollo’s handwriting _to Torsielli at Lambertville_ was the key to the whole mystery. There was no reason why Strollo should be writing to his own friend whom he saw daily and who lived beside him in the same town. Neither, argued Petrosino, would there be any reason for putting on a _two-cent_ stamp in a place so small as to have no mail delivery. Ergo, the envelope must have been intended to create the impression that it had been mailed from some other place, by another person—from whom but the fictitious brother? Bit by bit Petrosino built up a case entirely out of circumstantial evidence that demonstrated Strollo’s guilt to a mathematical certainty. So vivid was Petrosino’s account of his labors that in opening the case next day to the jury I had but to repeat the story I had heard the night before. Strollo was convicted after a week’s trial before Judge O’Gorman in the Criminal Term of the Supreme Court and paid the penalty of his treachery in the electric chair. For him I felt not one pang of pity or remorse. But during the preparation for the case the function of the detective as a decoy was demonstrated in a most effective manner. Strollo was confined in the House of Detention and a detective from head-quarters was introduced there as an ostensible prisoner, under the name of Silvio. Strollo and he became great friends, and when the former was removed to the Tombs the murderer wrote elaborately to the detective, requesting him to testify as a witness at the trial on his behalf and instructing him what to say in order to establish an alibi. Those letters were the last nails in Strollo’s coffin. After his conviction they were stolen by somebody and could not be included in the case on appeal, for which reason the court had some doubt as to whether the conviction should be affirmed. Before the Court of Appeals rendered its decision, however, I found, while cleaning out my safe, photographs of the letters which I had had taken as a precautionary measure, but the existence of which I had forgotten. I now have every important document that comes into my hands as evidence photographed as a matter of course.