“By the main entrance.  He left—­it was a quarter to three.  I know exactly.”

“The clock in the hall is stopped, Miss Innes,” said Jamieson.  Nothing seemed to escape him.

“He looked at his watch,” she replied, and I could see Mr. Jamieson’s snap, as if he had made a discovery.  As for myself, during the whole recital I had been plunged into the deepest amazement.

“Will you pardon me for a personal question?” The detective was a youngish man, and I thought he was somewhat embarrassed.  “What are your—­your relations with Mr. Bailey?”

Gertrude hesitated.  Then she came over and put her hand lovingly in mine.

“I am engaged to marry him,” she said simply.

I had grown so accustomed to surprises that I could only gasp again, and as for Gertrude, the hand that lay in mine was burning with fever.

“And—­after that,” Mr. Jamieson went on, “you went directly to bed?”

Gertrude hesitated.

“No,” she said finally.  “I—­I am not nervous, and after I had extinguished the light, I remembered something I had left in the billiard-room, and I felt my way back there through the darkness.”

“Will you tell me what it was you had forgotten?”

“I can not tell you,” she said slowly.  “I—­I did not leave the billiard-room at once—­”

“Why?” The detective’s tone was imperative.  “This is very important, Miss Innes.”

“I was crying,” Gertrude said in a low tone.  “When the French clock in the drawing-room struck three, I got up, and then—­I heard a step on the east porch, just outside the card-room.  Some one with a key was working with the latch, and I thought, of course, of Halsey.  When we took the house he called that his entrance, and he had carried a key for it ever since.  The door opened and I was about to ask what he had forgotten, when there was a flash and a report.  Some heavy body dropped, and, half crazed with terror and shock, I ran through the drawing-room and got up-stairs—­I scarcely remember how.”

She dropped into a chair, and I thought Mr. Jamieson must have finished.  But he was not through.

“You certainly clear your brother and Mr. Bailey admirably,” he said.  “The testimony is invaluable, especially in view of the fact that your brother and Mr. Armstrong had, I believe, quarreled rather seriously some time ago.”

“Nonsense,” I broke in.  “Things are bad enough, Mr. Jamieson, without inventing bad feeling where it doesn’t exist.  Gertrude, I don’t think Halsey knew the—­the murdered man, did he?”

But Mr. Jamieson was sure of his ground.

“The quarrel, I believe,” he persisted, “was about Mr. Armstrong’s conduct to you, Miss Gertrude.  He had been paying you unwelcome attentions.”

And I had never seen the man!