"Fortescue had started for St. Paul. Why had he not gone there? Instead, he was found south of the lake, in the woods, dead from a dagger thrust.
"Why had he the plans and memoranda in his possession? And where were the suit case and the plans?"
"Some thought he had been going to sell the plans to the agent of some foreign nation, that he was afraid the commercial traveler would tell of the mistake made in the hotel, and that he had got rid of the satchel and taken his own life. The bottom of the lake, just off the place where Fortescue was found, was dragged, but the satchel could not be found. Nor has it been found to this day."
Cameron paused.
"That's what happened, Cameron," said Matt. "Fortescue was treacherous. When he saw he had been discovered, his treasonable designs so worked upon him that he probably destroyed the satchel and the plans and killed himself."
"Wait, Motor Matt," proceeded Cameron; "there's more to it. The same day Fortescue started across Devil's Lake to take the train east, a soldier named Cant Phillips deserted from Fort Totten. This Phillips also came from the Presidio, and belonged with Fortescue's company. The soldier was never found—and this, you will remember, happened two years ago."
"But what has Phillips to do with Fortescue and the plans?"
"Here is where guesswork comes in. Ping found the knife on the spot where Siwash Charley and two of his villainous comrades carried the boy the night the aëroplane was tampered with. Suppose Siwash Charley had dropped the knife?"
"More likely," returned Matt, "Fortescue dropped it after he stabbed himself."
"No. The ground was searched all around in that vicinity, and the knife could not be found. If Fortescue gave himself a mortal wound, he would have had to drop the knife on the spot. It wasn't there at that time. The knife, as a matter of fact, hasn't laid so long in the woods as its appearance would indicate. The rust is only on the surface of the steel, and fifteen minutes' work will clean the dagger so that it will be almost as bright as ever. I don't think it has been in the woods more than two weeks. In short, it's my notion that Siwash Charley dropped it when he and his pals carried Ping to the place where he was left."