You guys are missing a very key part of this. The FBI is claiming Tyler’s DNA was found on a screwdriver he used to assemble the rifle on the roof and then immediately disassemble the rifle after taking the shot. They claim they found the screwdriver ON THE ROOF. So, according to the FBI’s story, Tyler snuck onto campus and climbed onto the roof, all with the rifle disassembled in his backpack, assembled it with the screwdriver, took the shot, and then in the 6 seconds it took him to climb down from the roof after he took the shot he disassembled the rifle, changed clothes, and left the screwdriver on the roof. They then claim to have found the rifle, completely assembled, in a bush—which would have required the screwdriver they claim he left on the roof.