His decision to visit the Thelma once more might have been due to the fact that it had been the scene of several mysterious incidents which were more or less directly traceable to the activities of Mr. Shei. The death of Virginia Darrow had occurred there, and the bullet that had missed The Gray Phantom by such a narrow margin was still imbedded in one of the pillars. But Culligore’s expression gave no indication of his purpose as he stood on the sidewalk across the street from the theater and glanced up at the windows of Vincent Starr’s private office on the second floor.

The windows were dark, so evidently Starr was not there, and the entire structure presented a gloomy and lifeless appearance. Culligore hummed a little tune as he walked to the nearest street intersection, then cut diagonally across the thoroughfare, continued half a block to the west, and finally ducked into a dark basement entrance. The ease with which he made his way suggested that he had traveled the same route before. After walking down a dirty and foul-smelling passage, he emerged into a vacant space bordered at one side by the rear wall of the theater.

He crossed the inclosure, then ran down a short stairway, and brought up against a door. Now he took a number of keys from his pocket and tried several in the lock before he found one that fitted. At last the door came open, and the lieutenant, locking it carefully behind him, stood in the basement under the Thelma Theater.

On all sides was total darkness. For a time he stood still, listening for sounds, but nothing but dull and distant noises from the outside reached his ears. Having satisfied himself that he was apparently alone in the basement, he took out his flash light and began a thorough and comprehensive search. With the electric flash peering into every nook and corner, he explored the dressing rooms, peeped behind piles of discarded scenery, examined odds and ends of stage property, looked into the barrels and boxes in the dusty storerooms, and even tapped the walls here and there to assure himself that there were no hollow spaces.

At last he gave up. His search had taken almost an hour and it had been complete and painstaking in every respect, yet Lieutenant Culligore seemed not quite satisfied. On his face was a look of hesitancy that seemed to suggest a lingering suspicion that something might have eluded him. Standing in the center of the basement, he extinguished the flash light, for it had been his experience that his other senses were more acute when his eyes received no impressions.

For a little while, standing in impenetrable darkness, he scarcely breathed. He had a curious sensation that a faint sound was passing him and dissolving in the dank air. It was so slight and elusive that his ears could scarcely detect it, yet it appealed to his imagination with peculiar insistence. It might have been either a moan or a sigh, or perhaps a cry coming from a great distance. Somehow, though he could not analyze the sensation, he fancied it expressed a great, overwhelming anguish. Whether it came from above, below, or the sides he could not determine, but it inspired him with a haunting feeling that he was not alone.

Again he took up the flash, and instantly the impression vanished, as if it had been a wraith fleeing from the light. Once more, step by step, he went over every square foot of the basement, covering the ground he had already searched so patiently, but he found nothing that gave the slightest clew to the peculiar sound. Finally, half inclined to believe that his imagination had deceived him, he ascended the stairway and continued his search on the ground floor. With dogged determination he explored the space in the wings and back of the stage, then went up and down the aisles in the auditorium. His inspection of the boxes was fruitless, and he found nothing of significance in the little niche where, on his previous visit to the Thelma, he had strongly suspected that an eavesdropper was hiding. Finally he went through the offices on the street front, occupied, as was indicated by the brass plates on the doors, by the treasurer, business manager, and stage director. Here also his quest was unavailing, and nothing now remained but Vincent Starr’s private office on the upper floor.

The moment he entered, Culligore felt as though he were invading the den of a sybarite. His flash light, flitting slowly over the room, revealed soft color harmonies and exquisite decorations. Faint and delicate perfumes mingled with the fresh and alluring scents of flowers. Culligore’s feet sank deep into costly rugs as he moved about the office, peeping behind chairs, desks, and cabinets, and occasionally sounding the walls for hollow spaces. After an hour of intense and patient effort, he was forced to admit that he had exerted himself needlessly and that his impressions while standing in the basement could have been nothing but figments of his fancy.

Finally he sat down in the luxuriously upholstered chair beside Starr’s desk. His watch showed a quarter past eleven, and he tried to reconcile himself to the thought that the only thing he could do was to go home and sleep. He was disappointed, for he had hoped that his search would yield some tangible results. He scowled a little as his gaze roamed idly over the orderly piles of papers on the desk. The ink stand, the paper cutter, and the pens were all of ornamental design. The only plain and undecorative objects in the room were the two telephones standing at one side of the desk. It struck him as a little odd that there should be two of them, but then he noticed that one was an automatic instrument without outside connections and communicating only with the various departments in the building.

Presently he yawned ostentatiously. He could not quite understand his reason for remaining after his fruitless task was done, nor could he comprehend the feeling, vague but uncannily persistent, that the next few minutes would bring some startling developments.