Lieutenant Valcour picked the slipper up and sighed. It was a distressingly leading and decisive clue, but it did not lead in a direction he cared to follow, nor did it decide things as he thought they ought to be decided.

On the surface of it, the case seemed blatantly plain: Hollander had come to the house at seven to save Mrs. Endicott from committing murder or suicide and had shocked Endicott almost to death⁠—and just a short while ago Mrs. Endicott had shot her husband to prevent him from making a statement that would convict Hollander.

Rubbish!

Lieutenant Valcour flatly refused to believe it. And yet one had to believe that Hollander had certainly intended to stab Endicott with that knife; the point was irrefutable. Furthermore, Hollander’s motives remained clear enough and beautifully simple: he wanted to protect Mrs. Endicott.

But what about her motives?

And Roberts’s?

And as a kernel to the whole perplexing enigma, what had been the object of the search through Endicott’s pockets and among the papers in the left-hand upper drawer of his desk?

There was nothing to be gained, however, by standing outside on the balcony and admiring the flushing sky and breathing in with the manner of a connoisseur the morning air. Lieutenant Valcour returned, via the bathroom window, to Endicott’s room.

“The night’s almost over, Lieutenant,” said Cassidy by way of greeting.

“Almost over, Cassidy.”

“And it’s been a hell of a night, too, if you don’t mind my saying it.”

“I don’t mind your saying it.”

“Especially for him.”

Cassidy jerked a muscular thumb toward the bed.

“Least of all for him, Cassidy.”

“He may be well out of it at that.”

“He is. There’s a lot of beautiful tripe written about how all people kill the things they love. Metaphysically, perhaps. But with a bullet, Cassidy? Not so.”

“I don’t get you, Lieutenant.”

“That isn’t strange, Cassidy. So far I don’t even get myself.”

Lieutenant Valcour went to the door and opened it. Hansen was standing outside, and in his hand was a gun wrapped in a clean handkerchief.

“Roberts’s gun, Hansen?”

“Yes, Lieutenant. It was just where you said it would be, in the trunk. I wrapped it in a handkerchief to keep any prints you might want on it.”

“That’s right, Hansen. Go upstairs now and wake up Dr. Worth. Ask him if he will please come down here at once.”

“Yes, Lieutenant.” Hansen hesitated for a minute.

“Well, what is it, Hansen?”

“I understood you all right didn’t I, sir,” Hansen said uncomfortably, “when you told me that maid wasn’t to be put under arrest?”

“Yes. I don’t want to do anything about her as yet. Later on we may book her on a violation of the Sullivan Law and again we may not.”

“Yes, sir.”

Lieutenant Valcour took the gun and went back into the room with it, closing the door. He carefully unfolded enough of the handkerchief so that the barrel was exposed. He sniffed this and decided that the gun had neither been recently fired nor cleaned. There was just the definite odourlessness which one finds with guns that have not been used or taken care of for a very long time. So far, then, he was inclined to believe that Roberts’s story was correct.

“Is that the rod that done the trick, Lieutenant?” said Cassidy, who had been keenly interested in the sniffings.

“No, it isn’t, Cassidy. This gun hasn’t been fired for years, maybe.”

“Well, I wish it was. I’d like to get out of this joint.”

“Still nervous, Cassidy?”

“No, I ain’t nervous, Lieutenant. I’m just uncomfortable. It’s like there was something in this case that hasn’t broken yet. You know what I mean? Something we ain’t so much as put a finger on.”

Lieutenant Valcour knew very well just exactly what Cassidy meant. He, too, felt that same indefinable effect of impending “somethings” that were connected with obscure danger. It was an emotion, however, which required official scowlings. After all, psychic patrolmen were not considered as being to the best interests of the force. One shouldn’t be allowed, really, to graduate into psychic realms anywhere below the rank of lieutenant.

“Discounting your weekly adventures between paper covers, this is your first real murder case, isn’t it, Cassidy?”

“I thank God it is, sir.”

“Well, you’ll get used to them after a while. Before you’re called in on your fourth or fifth you’ll be finished with having presentiments.”

“Will they be likely to be like this one, sir?”

“That will depend entirely, Cassidy, upon just how much publicity this one is given in the papers, as well as on the supply at hand of potential victims who have weak hearts. I dare say the method will become fashionable for a while.” There was a peevish rap on the door. “Ah, come in, Doctor.”

Dr. Worth was just as peevish as his knock. The camel’s-hair dressing gown in which he was still bundled hinted blurringly at indignant muscles that quivered beneath its loose folds. His hair was rumpled-looking and frowsy.

“Really, Lieutenant,” he began, “this is getting to be beyond a joke.”

“I’m sorry, Doctor, but I had to discuss Mrs. Endicott’s condition with you most seriously and at once.”

Dr. Worth paled a little at this.

“Nothing’s happened to her, too, has there?”

“No, Doctor, nothing has. And I don’t think that just now I could stand another murder. It’s about her physical condition in general. Is her heart all right?”

Dr. Worth’s curiosity was beginning to get the upper hand over his grouch.

“Perfectly sound. Why do you ask?”

“Because I want to try an experiment on her.”

“You want to what, sir?” Dr. Worth almost shouted it. He was thoroughly awake now.

“Not so loud, please, Doctor. I want you to let me stay in the room alone with your patient. You can open the connecting bathroom door a little and watch me through its crack, but I want the nurse out of the way. And I don’t want you to make any noise or comments while you’re watching. I don’t want Mrs. Endicott to know that you’re there.”

Dr. Worth looked at Lieutenant Valcour sharply. “This is nonsense. She couldn’t possibly tell who was or who wasn’t there. She’s unconscious.”

“Perhaps she isn’t, Doctor. This is what her maid has just told me.” Lieutenant Valcour offered Dr. Worth Roberts’s astonishing theory concerning the poured-out narcotic, and Dr. Worth was quite properly astonished. “So you see it’s a possibility, Doctor, and the fact of my finding that slipper outside of the window makes it practically a certainty.”

“It’s the most astounding thing I’ve ever heard of in my life. If you don’t intend to shock her, Lieutenant, I’ll agree to anything you say.”

“I shan’t do anything rough, Doctor, like discharging a gun off near her ear, or pinching her, or slapping her, or any of the tricks which are so popularly supposed to be kept up the sleeve of a policeman. You can stop me at any minute if you object to anything I may be doing.”

“Have you planned just what you will do?”

“With a woman like Mrs. Endicott there wouldn’t be any use in planning anything. All that I can do in advance is to create an atmosphere and then do whatever occurs to me as being best when the proper time comes. There won’t be anything complicated about it.”

“Just what sort of an atmosphere, Lieutenant?”

“Well, in the first place I’ll call the nurse outside into the corridor and you can tell her not to go back in again until I say so. You might suggest to her that she go down to the kitchen and make some coffee⁠—she seems a little dippy about coffee⁠—or something. Then we’ll leave Mrs. Endicott quite alone in her room for a minute or two. If she’s really faking, she’ll begin to worry about what is going on. Then the door will open again and, instead of the nurse, I’ll come in. She’ll be pretty certain to suspect that I’ve found the slipper, but will be all the more careful to keep up her pretence of being under the influence of the narcotic. If she gets away with that, you know, she can always claim that Roberts herself must have dropped the slipper onto the balcony as a plant. The main thing is that Mrs. Endicott won’t know just what’s up, and when a woman of her temperament can’t figure a thing out mentally, it about drives her crazy.”

“Then I suppose, Lieutenant, that when you get her into this receptive state you’ll speak to her?”

Lieutenant Valcour laughed. “On the contrary, Doctor, I haven’t the slightest intention of saying a single word. Shall we go now? After you’ve arranged things with Nurse Vickers you can come back in here again and start watching from the bathroom.”

They went outside, and Lieutenant Valcour rapped softly on Mrs. Endicott’s door. It opened a bit, and Nurse Vickers looked out. She saw Dr. Worth and came outside, shutting the door behind her.

“You wanted to see me, Doctor?”

“Yes, Miss Vickers. How is Mrs. Endicott?”

“Quite comfortable, Doctor. She’s breathing as peacefully as a child.”

“There haven’t been any signs of restlessness?”

“Oh, no, Doctor. She hasn’t budged since I’ve been watching her.”

Dr. Worth mildly raised his eyebrows. “That in itself is rather curious,” he said.

“Curious, Doctor?”

“Oh, nothing to be alarmed at, Miss Vickers. You look a little tired. Run downstairs and drink some coffee. The lieutenant, here, will stay with Mrs. Endicott, and you’re not to go back into her room again until he says so.”

“Help!” thought Lieutenant Valcour. As a detective Dr. Worth was a darned fine doctor. Miss Vickers, as he had expected, was instantly curious.

“Something more wrong, Doctor?”

“No Miss Vickers,” Lieutenant Valcour said coldly. “Please do as the doctor instructed, and at once.”

“Oh.”

Nurse Vickers, feeling a little outraged, vanished toward the stairs.

“Shall I go and stand by the bathroom door now?” said Dr. Worth.

“If you wish. Don’t make the slightest sound when you’re opening it, and don’t open it more than an inch at the most, please.”

“I won’t, Lieutenant.”

Dr. Worth, feeling very much like one of those fabulous characters he had read about in Fenimore Cooper when a child, went back into Endicott’s room.

Lieutenant Valcour waited another full minute before he opened the door and went inside. He did not look at Mrs. Endicott, but walked softly over to a chair, lifted it, and placed it close beside the bed. He drew the slipper from his pocket and sat down.

There was an utter and complete hush. For three minutes⁠—he timed himself with his wrist watch⁠—he sat motionless and stared at the closed lids of Mrs. Endicott’s eyes.

Then he began to tap the slipper quite softly, but quite persistently and with a rhythmic regularity, upon an arm of the chair.

Tap⁠—tap⁠—tap⁠—tap⁠—tap⁠—

Mrs. Endicott’s face retained the smooth expressionlessness of slumber.

Tap⁠—tap⁠—tap⁠—

Her breathing held the steady depths of sleep.

Tap⁠—tap⁠—tap⁠—tap⁠—

“If you do that much longer,” she said quietly, “I shall go insane.”