I think that Tiger Tiger the secret organization with in the law enforcement of California is responsible for the Red John killings the person behind all the hits is obviously someone who is supposedly dead, I think Patrick Jane's wife is the real killer. The men Patrick Jane keeps getting calls from are pattsy's for the real killer and is a legacy of Patrick's family including his child. It was originally his wife's parents. This is a conspiracy after all and the least likely person is someone who Patrick is trying to get revenge for.