How does Harper react when he realizes the killer is close?

When Harper realizes that the killer is getting close to where he and Drewe are in his study, Harper goes into action. He locks the office door, tells Miles to send FBI agents to the farmhouse, and calls Bob Anderson. Bob and Patrick had gone to the cemetery, so Harper calls the FBI agents posted there. He gets a gun for himself and for Drewe, and then he has Drewe type a long note to the killer. He fills a printer cartridge with gun powder and rigs it to explode when someone touches a key on the keyboard.