The detective seemed both puzzled and disturbed.  “Well, it looked like the shadow of a bat.  I’ll say that for it,” he said finally.

On the heels of his words the front door bell began to ring.  All turned in the direction of the hall.

“I’ll answer that!” said Jack Bailey eagerly.

Miss Cornelia gave him the key to the front door.

“Don’t admit anyone till you know who it is,” she said.  Bailey nodded and disappeared into the hall.  The others waited tensely.  Miss Cornelia’s hand crept toward the revolver lying on the table where Anderson had put it down.

There was the click of an opening door, the noise of a little scuffle—­then men’s voices raised in an angry dispute.  “What do I know about a flashlight?” cried an irritated voice.  “I haven’t got a pocket-flash—­take your hands off me!” Bailey’s voice answered the other voice, grim, threatening.  The scuffle resumed.

Then Doctor Wells burst suddenly into the room, closely followed by Bailey.  The Doctor’s tie was askew—­he looked ruffled and enraged.  Bailey followed him vigilantly, seeming not quite sure whether to allow him to enter or not.

“My dear Miss Van Gorder,” began the Doctor in tones of high dudgeon, “won’t you instruct your servants that even if I do make a late call, I am not to be received with violence?”

“I asked you if you had a pocket-flash about you!” answered Bailey indignantly.  “If you call a question like that violence—­” He seemed about to restrain the Doctor by physical force.

Miss Cornelia quelled the teapot-tempest.

“It’s all right, Brooks,” she said, taking the front door key from his hand and putting it back on the table.  She turned to Doctor Wells.

“You see, Doctor Wells,” she explained, “just a moment before you rang the doorbell a circle of white light was thrown on those window shades.”

The Doctor laughed with a certain relief.

“Why, that was probably the searchlight from my car!” he said.  “I noticed as I drove up that it fell directly on that window.”

His explanation seemed to satisfy all present but Lizzie.  She regarded him with a deep suspicion. “’He may be a lawyer, a merchant, a Doctor...’” she chanted ominously to herself.

Miss Cornelia, too, was not entirely at ease.

“In the center of this ring of light,” she proceeded, her eyes on the Doctor’s calm countenance, “was an almost perfect silhouette of a bat.”

“A bat!” The Doctor seemed at sea.  “Ah, I see—­the symbol of the criminal of that name.”  He laughed again.

“I think I can explain what you saw.  Quite often my headlights collect insects at night and a large moth, spread on the glass, would give precisely the effect you speak of.  Just to satisfy you, I’ll go out and take a look.”

He turned to do so.  Then he caught sight of the raincoat-covered huddle on the floor.