I am not sure precisely who red john is, but my theory centers around 2 key points. 1.) I believe "he is mar" was the beginnings of he is MARRIED. Shortly before O'laughlin is killed he takes back the necklace that he told Grace "it was my mothers." I think that the locket may be a clue to who red john's wife may be, as i suspect o'laughlin to be red john's son. I also believe kirkland to be a son of Red john's, which would put RJ at an age i always suspected, in his 50's. My theory is that RJ's family is a police family, i would imagine at some point Rj was in the FBI and trained his sons and had them placed there. He clearly has training in counter forensics and is always a step ahead, while maintaining access to CBI, FBI, and Homeland security computers, etc. Kirkland asking to be kept in the loop as a favor i suspect was a directive from his father.