The person who is Red John would have been alarmed by Patrick's address. They would have known that this is where Patrick's family was killed. This person must have suspected that Patrick wanted revenge and probably planned an exit strategy - e.g. Planned the bomb or an explosion to distract and escape.

I don't like anyone on the list but if I had to pick I would pick Haffner. He is the only one who is similar to Patrick: about the same age, same height, relatively attractive (not close to Patrick's Devine level of attractiveness but more attractive than the rest) and charismatic... The perfect Red John would have been Mashburn!