“What tophats were there whose _presence_ was not out of the ordinary—so natural and in so natural a place that they were not even questioned? In the Roman Theatre, where all the costumes were hired from Le Brun, the answer is simply: the rented tophats being used for purposes of the play. Where would such tophats be? Either in the actors’ dressing-rooms or in the general wardrobe room backstage. When Ellery had reached this point in his reasoning he took Mrs. Phillips backstage and checked up on every tophat in the actors’ rooms and the wardrobe room. Every tophat there—and all were accounted for, none being missing—was a property tophat bearing on its lining the Le Brun insignia. Field’s hat, which we had proved to be a Browne Bros. topper, was not among the property tophats or anywhere backstage. “Since no one left the theatre Monday night with more than one tophat, and since Monte Field’s hat was unquestionably taken out of the theatre that same night, it was positively established that the murderer’s own tophat must have been in the Roman all the time the house was sealed, and was still there at the time of our second search. Now, the only tophats remaining in the theatre were property tophats. It therefore follows that the murderer’s own tophat (which he was forced to leave behind because he walked out with Field’s) _must_ have been one of the property hats backstage, since, let me repeat, these were the only tophats of which it could physically have been one. “In other words—one of these property tophats backstage belonged to the man who left the theatre Monday night in full dress wearing Field’s silk topper. “If this man were the murderer—and he could scarcely be anyone else—then our field of inquiry was narrowed to a considerable degree. He could only have been either a male member of the cast who left the theatre in evening clothes, or somebody closely connected with the theatre and similarly dressed. In the latter case, such a person would have had to have, first, a property tophat to leave behind; second, undisputed access to the wardrobe and dressing-rooms; and, third, the opportunity to leave his property tophat in either place.