“Doctor,” Lieutenant Valcour said, “our immediate concern is to find out who fired that shot. The principal reason is quite academic: we want to catch and arrest the person who did it. A secondary reason is that many people who reach the state of mental unbalance where they are impelled to commit murder don’t stop with the crime. They’ve tasted blood. They are in a state of abnormal acuteness, and are driven by a new fear: that of discovery and capture. To prevent being captured, they reason, why not kill again? There is nothing to be lost. You see, they can only be electrocuted once. I am presupposing, of course, that the criminal is an outsider⁠—some person at present hidden in the house, who will make some desperate effort at escape. It is a supposition that must be entertained, even though it is not a very good one. I believe that the facts will eventually prove the criminal to be a legitimate inmate.”

“That narrows the field, doesn’t it, Lieutenant, to whoever was in Mrs. Endicott’s room?”

“It does, unless somebody dropped a rope ladder from an upstairs window and got onto the balcony in that way. But I don’t put much stock in those tricks, Doctor, any more than I do in sliding panels and trapdoors. Outside of the badger game I’ve never come across a sliding panel in my life, and I don’t ever expect to, either.”

Dr. Worth was inclined to take the idea more seriously. “But a rope ladder⁠—there might very well be one around the house for an emergency fire escape.”

“All right, who was in the room just above this one? You. Did you come down a rope ladder and shoot Endicott?”

“God’s truth⁠—my dear man⁠—”

“Oh, be sensible, Doctor, of course you didn’t. And who had the room across the hall from you, which also is above the balcony? Mrs. Siddons, the housekeeper. If you saw her, you’d scarcely picture her as hurrying up and down a rope ladder. No, Doctor, whoever was on that balcony came from Mrs. Endicott’s room. We’re back to the same three people: Mrs. Endicott, her maid, and her nurse.”

“But Mrs. Endicott is out of the question, Lieutenant. She is still under the influence of the narcotic I gave her.”

“How about the nurse, Doctor? Have you known her long?”

“Known her? Only for the several cases she has worked on with me. But she comes from the most reputable agency in the city. How about the maid?”

“I don’t know.”

“She is just as good a candidate for suspicion as Miss Vickers, isn’t she? Why under the sun should Miss Vickers want to shoot Endicott?”

“I’m not seriously considering Miss Vickers at all. It’s perfectly obvious that whoever did shoot Endicott was either directly responsible for the earlier attack during the evening or else involved in it as an accomplice.”

“That might still include the maid.”

“It certainly might. I wonder if you’d mind asking Miss Vickers to come in here. I’d like to question her first.”

Dr. Worth nodded toward Endicott’s body, covered with a sheet on the bed. “Miss Vickers, Lieutenant, being a nurse is naturally accustomed to seeing the dead, but it will be rather gruesome for the maid if you question her in here, too.”

“Very gruesome, Doctor.”

“Well, you know best. You’re liable to have a fine case of hysterics on your hands.”

“I’ll risk it.”

Dr. Worth left and closed the door. There again swept over Lieutenant Valcour, with the solitude, that indefinable feeling of some lurking dread. There were voices crying out to him from the subconscious, warning him of dangers that were very real, very close at hand⁠—but the messages were indecisive, as are all instinctive things which fall beyond the charted seas of any human knowledge.

Nurse Vickers came in without the formality of knocking. Her glance toward the bed was professional and not coloured by any sign of nervousness.

“Thank you for coming, Miss Vickers. I’ll only bother you for a minute.”

“No bother at all, Lieutenant.”

“There is just one thing I want to know: who was in the room with you and your patient at the time of the shooting?”

“Why, I couldn’t say, Lieutenant, exactly.”

“Why not, Miss Vickers?”

“Because I wasn’t there myself. I was down in the kitchen making some coffee. I left Roberts with Mrs. Endicott. You see, there wasn’t anything that had to be done except just to be there. I’m sure it was quite all right.”

“Of course it was. I’m not suggesting for a minute, Miss Vickers, that I thought otherwise.” Lieutenant Valcour studied the woman for a second and then said, “I just wanted to know if you could help me check up on the number of shots that were fired.”

“I didn’t hear any shots at all, Lieutenant, ’way down there in that kitchen.”

Lieutenant Valcour wondered at this. The sound of one shot might well have been heard down in the kitchen: the shot which had killed Endicott and which had been fired from the balcony. The sound would surely have travelled clearly in the still night air and to the kitchen from outside. And yet he believed Nurse Vickers implicitly in her statement that she had heard no shot. There was no earthly reason why she should lie about it. The fact convinced him that whoever had fired had held the pistol inside of the window. He glanced at the sash and realized that the opening afforded plenty of room for a hand holding a gun to reach through.

“No,” he said, “I suppose you couldn’t have heard anything at all. Maybe Roberts can help me. She was in the room, wasn’t she, when you came back?”

“Oh, yes, Lieutenant, and terribly excited about the shooting. She seemed so upset, in fact, that if there hadn’t been so many much more important things for Dr. Worth to attend to, I’d have asked him to give her something to quiet her.”

“One can hardly blame Roberts,” Lieutenant Valcour said. “The fusillade must have been quite a shock, you know. And then everyone’s nerves are on edge tonight anyway. In just what fashion was she upset, Miss Vickers? From your professional experience, I mean, you probably could diagnose her actions. Was it fright⁠—nervous shock?”

“Oh, fright, of course, Lieutenant. I’ve seen lots of nervous and hysterical people during my work but never one as badly off as she was. I’m not exaggerating one bit when I say that she was gripped with an hysterical sort of terror.”

“Really. As bad as that?”

“Why, I was almost afraid even to let her stay in the room with the patient. The poor creature actually seemed to blame Mrs. Endicott in some fashion for what had happened. Just imagine this, Lieutenant: when I came in she was literally leaning over the bed and shaking her fist at Mrs. Endicott.”

“You are quite certain of this, Miss Vickers?”

“I saw it with my own eyes, Lieutenant.”

“And was Roberts saying anything?”

“Just the jumble that people go in for when they’re hysterical.”

“You couldn’t catch anything connected?”

“I didn’t try, Lieutenant. I had to get her away from the bed and calm her down.”

“You were able to?”

“I was. She calmed down quite suddenly and became perfectly normal again. I persuaded her to run downstairs and make herself a good bracing cup of tea.”

“Possibly carrying the pistol with her,” Lieutenant Valcour thought bitterly, “to hide it in some place where it might never be found.”

“Did she come back into the room afterward?” he said.

“Well, not really, Lieutenant. I know how particular you police officers are about the littlest details. She just stopped at the door to tell me she was feeling all right again. She said she was going upstairs to her room to take a little rest.”

“And you’re quite sure, Miss Vickers, that you can’t recall any of the words that Roberts was saying when you found her leaning over the bed?”

“I would if I could, Lieutenant. It was just a jumble. Ice⁠—something about ‘ice and human hearts.’ Then she switched to ‘searing flames’ and I don’t know what all else.”

“Would it bother you very much to go up to her room and see whether she’s in condition to come down here for a few minutes?”

“Why, not at all. I’d be glad to.”

“Thank you, Miss Vickers. You’ve helped me tremendously. Oh, there’s just one thing, Miss Vickers.”

Miss Vickers paused at the doorway.

“Yes, Lieutenant?”

“When you came back upstairs from the kitchen, did you notice anything about the atmosphere of Mrs. Endicott’s room?”

“Why⁠—I don’t know⁠—you mean a sense of tension or something?”

“No, I don’t. I mean was it as warm as when you left it, or cooler, or what?”

“Yes, I do, too⁠—it was cooler⁠—much. Because I remember after I quieted Roberts I went over to one of the radiators to see if the heat was still turned on. I thought Roberts must have turned it off, although I couldn’t for the life of me see why. But the radiator was quite hot, so I realized it must have been just the change from the kitchen. It’s a hot kitchen.”

“That is probably just what it was. Would you send Roberts to me now, please?”

“I will, Lieutenant.”

“Thank you.”

Miss Vickers went out and closed the door.

Lieutenant Valcour then did a rather horrible thing. He went over to the bed and pulled down enough of the sheet so that Endicott’s face was exposed.

And then he sat down and waited for Roberts.