Joe happened to see the second crash, and he didn't go to noon mess at all. He hadn't any appetite. Instead, he gloomily let himself be packed full of irrelevant information by the young lieutenant who considered that since Joe had been sent by security to look into sabotage, he must be given every possible opportunity to evaluate--that would be the word the young lieutenant would use--the situation. But all the time that Joe followed him about, his mind fumbled with a hunch. The idea was that there was a pattern of thinking in sabotage, and if you could solve it, you could outguess the saboteur. But the trouble was to figure out the similarity he felt existed in--say--a private plane shooting rockets and overhaul mechanics planting booby traps and faked shippers getting bombs on planes--and come to think of it, there was Braun.... Braun was the key! Braun had been an honest man, with an honest loyalty to the United States which had given him refuge. But he had been blackmailed into accepting a container of atomic death to be released in the Shed. Radioactive cobalt did not belong in the Shed. That was the key to the pattern of sabotage. Braun was not to use any natural thing that belonged in the Shed. He was to be only the means by which something extraneous and deadly was to have been introduced. That was it! Somebody was devising ingenious ways to get well-known destructive devices into places where they did not belong, but where they would be effective. Rockets. Bombs. Even radioactive cobalt dust. All were perfectly well-known means of destruction. The minds that planned those tricks said, in effect: "These things will destroy. How can we get them to where they will destroy something?" It was a strict pattern. But the pushpot sabotage--and Joe was sure it was nothing else--was not that sort of thing. Making motors explode.... Motors don't explode. One couldn't put bombs in them. There wasn't room. The explosions Joe had seen looked as if they'd centered in the fire basket--technically the combustion area--behind the compressor and before the drive vanes. A jet motor whirled. Its front vanes compressed air, and a flame burned furiously in the compressed air, which swelled enormously and poured out past other vanes that took power from it to drive the compressor. The excess of blast poured out astern in a blue-white flame, driving the ship. But one couldn't put a bomb in a fire basket. The temperature would melt anything but the refractory alloys of which a jet motor has to be built. A bomb placed there would explode the instant a motor was started. It couldn't resist until the pushpot took off. It couldn't.... This was a different kind of sabotage. There was a different mind at work.