The last scene we saw inside Jane's house was...Stiles and Haffner sitting on the sofa(where McCallister sat before Jane tell him to get up).Jane who is not killed is nearest to the sofa than Bertram,Smith and McCallister...We know that Bertram ,Smith and Jane are alive.So McCallister must be alive too because it was standing far from the sofa than Jane...So the bomb must be inside the sofa or near him...My guess.The bomb was inside McCallister's police hat thats why Stiles and Haffner are dead and the others alive...Smart move Red John(Sheriff Thomas McCallister)!!!Really smart!!