"Petromortis?" repeated Snedden, who, for the first time, began to show interest in what was going on about him. "Then it was an accident?"
"I did not say it was an accident," corrected Craig. "There is an old adage that murder will out. And this expression of human experience is only repeated in what we modern scientific detectives are doing. No man bent on the commission of a crime can so arrange the circumstances of that crime that it will afterward appear, point by point, as an accident."
Kennedy had us all following him breathlessly now.
"I do not consider it an accident," he went on, rapidly piecing together the facts as we had found them. "Ida Snedden was killed because she was getting too close to some one's secret. Even at luncheon, I could see that she had discovered Gertrude's attachment for Garretson. How she heard that, following the excitement of the explosion this afternoon, Gertrude and Garretson had disappeared, I do not pretend to know. But it is evident that she did hear, that she went out and took Jackson's car, probably to pursue them. If we have heard that they went by the river road, she might have heard it, too.
"In all probability she came along just in time to surprise some one working on the other side of the old merry-go-round structure. There can be no reason to conceal the fact longer. From that deserted building some one was daily launching a newly designed invisible aeroplane. As Mrs. Snedden came along, she must have been just in time to see that person at his secret hangar. What happened I do not know, except that she must have run the car off the river road and into the building. The person whom she found must have suddenly conceived a method of getting her out of the way and making it look like an accident of some kind, perhaps persuaded her to stay in the car with the engine running, while he went off and destroyed the aeroplane which was damning evidence now."
Startling as was the revelation of an actual phantom destroyer, our minds were more aroused as to who might be the criminal who had employed such an engine of death.
Kennedy drew from his pocket the telegram which had just arrived, and spread it out flat before us on a table. It was dated Philadelphia, and read:
MRS. IDA SNEDDEN, Nitropolis:
Garretson and Gertrude were married to-day. Have traced them to the
Wolcott. Try to reconcile Mr. Snedden.