She smoked a moment pensively, and went on:
“Yes, there must be a motive back of it all—though for the life of me I can’t suggest one. Of course Julia was a vinegary, unpleasant person, but she went out very little, and worked off her various complexes on the family. And yet, she may have been leading a double life for all I know. When these sour old maids break loose from their inhibitions I understand they do the most utterly utter things. But I just can’t bring my mind to picture Julia with a bevy of jealous Romeos.” She made a comical grimace at the thought. “Ada, on the other hand, is what we used to call in algebra an unknown quantity. No one but dad knew where she came from, and he would never tell. To be sure, she doesn’t get much time to run around—mother keeps her too busy. But she’s young and good-looking in a common sort of way”—there was a tinge of venom in this remark—“and you can’t tell what connections she may have formed outside the sacred portals of the Greene mansion.—As for Chet, no one seemed to love him passionately. I never heard anybody say a good word for him but the golf pro at the club, and that was only because Chet tipped him like a parvenu. He had a genius for antagonizing people. Several motives for the shooting might be found in his past.”
“I note that you’ve changed your ideas considerably in regard to the culpability of Miss Ada.” Vance spoke incuriously.
Sibella looked a little shamefaced.
“I did get a bit excited, didn’t I?” Then a defiance came into her voice. “But just the same, she doesn’t belong here. And she’s a sneaky little cat. She’d dearly love to see us all nicely murdered. The only person that seems to like her is cook; but then, Gertrude’s a sentimental German who likes everybody. She feeds half the stray cats and dogs in the neighborhood. Our rear yard is a regular pound in summer.”
Vance was silent for a while. Suddenly he looked up.
“I gather from your remarks, Miss Greene, that you now regard the shootings as the acts of some one from the outside.”
“Does any one think anything else?” she asked, with startled anxiety. “I understand there were footprints in the snow both times we were visited. Surely they would indicate an outsider.”
“Quite true,” Vance assured her, a bit overemphatically, obviously striving to allay whatever fears his queries may have aroused in her. “Those footprints undeniably indicate that the intruder entered each time by the front door.”
“And you are not to have any uneasiness about the future, Miss Greene,” added Markham. “I shall give orders to-day to have a strict guard placed over the house, front and rear, until there is no longer the slightest danger of a recurrence of what has taken place here.”