“It’s astonishing. But after the accusation, when Ada knew that Sibella suspected her, why didn’t she kill Sibella next?”
“She was too canny. It would have tended to give weight to Sibella’s accusation. Oh, Ada played her hand perfectly.”
“Go on with the story, sir,” urged Heath, intolerant of these side issues.
“Very well, Sergeant.” Vance shifted more comfortably into his chair. “But first we must revert to the weather; for the weather ran like a sinister motif through all that followed. The second night after Julia’s death it was quite warm, and the snow had melted considerably. That was the night chosen by Ada to retrieve the gun. A wound like hers rarely keeps one in bed over forty-eight hours; and Ada was well enough on Wednesday night to slip into a coat, step out on the balcony, and walk down the few steps to where the gun lay hidden. She merely brought it back and took it to bed with her—the last place anyone would have thought to look for it. Then she waited patiently for the snow to fall again—which it did the next night, stopping, as you may remember, about eleven o’clock. The stage was set. The second act of the tragedy was about to begin. …
“Ada rose quietly, put on her coat, and went down to the library. Getting into the galoshes, she again walked to the front gate and back. Then she went directly upstairs so that her tracks would show on the marble steps, and hid the galoshes temporarily in the linen-closet. That was the shuffling sound and the closing door that Rex heard a few minutes before Chester was shot. Ada, you recall, told us afterward she had heard nothing; but when we repeated Rex’s story to her she became frightened and conveniently remembered having heard a door close. My word! That was a ticklish moment for her. But she certainly carried it off well. And I can now understand her obvious relief when we showed her the pattern of the footprints and let her think we believed the murderer came from outside. … Well, after she had removed the galoshes and put them in the linen-closet, she took off her coat, donned a dressing-gown, and went to Chester’s room—probably opened the door without knocking, and went in with a friendly greeting. I picture her as sitting on the arm of Chester’s chair, or the edge of the desk, and then, in the midst of some trivial remark, drawing the revolver, placing it against his breast, and pulling the trigger before he had time to recover from his horrified astonishment. He moved instinctively, though, just as the weapon exploded—which would account for the diagonal course of the bullet. Then Ada returned quickly to her own room and got into bed. Thus was another chapter written in the Greene tragedy.”
“Did it strike you as strange,” asked Markham, “that Von Blon was not at his office during the commission of either of the crimes?”
“At first—yes. But, after all, there was nothing unusual in the fact that a doctor should have been out at that time of night.”
“It’s easy enough to see how Ada got rid of Julia and Chester,” grumbled Heath. “But what stops me is how she murdered Rex.”
“Really, y’ know, Sergeant,” returned Vance, “that trick of hers shouldn’t cause you any perplexity. I’ll never forgive myself for not having guessed it long ago—Ada certainly gave us enough clues to work on. But, before I describe it to you, let me recall a certain architectural detail of the Greene mansion. There is a Tudor fireplace, with carved wooden panels, in Ada’s room, and another fireplace—a duplicate of Ada’s—in Rex’s room; and these two fireplaces are back to back on the same wall. The Greene house, as you know, is very old, and at some time in the past—perhaps when the fireplaces were built—an aperture was made between the two rooms, running from one of the panels in Ada’s mantel to the corresponding panel in Rex’s mantel. This miniature tunnel is about six inches square—the exact size of the panels—and a little over two feet long, or the depth of the two mantels and the wall. It was originally used, I imagine, for private communication between the two rooms. But that point is immaterial. The fact remains that such a shaft exists—I verified it tonight on my way downtown from the hospital. I might also add that the panel at either end of the shaft is on a spring hinge, so that when it is opened and released it closes automatically, snapping back into place without giving any indication that it is anything more than a solid part of the woodwork—”
“I get you!” exclaimed Heath, with the excitement of satisfaction. “Rex was shot by the old man-killing safe idea: the burglar opens the safe door and gets a bullet in his head from a stationary gun.”
“Exactly. And the same device has been used in scores of murders. In the early days out West an enemy would go to a rancher’s cabin during the tenant’s absence, hang a shotgun from the ceiling over the door, and tie one end of a string to the trigger and the other end to the latch. When the rancher returned—perhaps days later—his brains would be blown out as he entered his cabin; and the murderer would, at the time, be in another part of the country.”
“Sure!” The Sergeant’s eyes sparkled. “There was a shooting like that in Atlanta two years ago—Boscomb was the name of the murdered man. And in Richmond, Virginia—”
“There have been many instances of it, Sergeant. Gross quotes two famous Austrian cases, and also has something to say about this method in general.”
Again he opened the Handbuch.
“On page 943 Gross remarks: ‘The latest American safety devices have nothing to do with the safe itself, and can in fact be used with any receptacle. They act through chemicals or automatic firing devices, and their object is to make the
