As others have mentioned Haffner is the closest of the final seven to being a parallel to Jane...They both like Lisbon and are on a first name basis with her...They are both fit, handsome and look young for their age...both dress well at all times...both seldom let their emotions get the best of them...same height....same build...same natural charm...
If you met the seven suspects at a party he's the last one you would think was a criminal...that would be important for Red John... He would need to seduce his marks without giving off any warning signals....
Somehow him and Lorelei as lovers just feels right...The Hafner and Lorelei relationship being a parallel to Lisbon and Jane...Could you see any of the other suspects as lovers to Lorelei ? Realistically ?
Hafner is neither muscular nor scrawny nor fat....He fits the description of the blind woman to a tee...much more than any other final suspect
Hafner is affiliated with two of the most powerful organizations in California...The CBI and Visualize...
The CBI gives him access to powerful people in law enforcement...and gave him training in techniques to cover up crimes....Remember RJ's first crime when he was still making mistakes ? Was this before Haffner became a police officer ?
Haffner was a member of Visualize before he joined CBI...this gave him training in psychological manipulation....He's the only suspect with a probable tie to The Red Barn murders...Lisbon asks him if he was involved in the murders...He gives a very cryptic answer...
Animals were tortured and kiled at the Red Barn farm...Animal mistreatment is often a precursor to a man becoming a serial killer...Ray is the only suspect with known link to the Red Barn...
Ray Haffner offered Lisbon a position with his organization in season 5....Was that organization a front for Tyger Tyger ?
His time with Visualize would give him experience in starting a cult...Perfect for starting an organization like Tyger Tyger...
Jane only reveals his true self to one person....Lisbon...Haffner only reveals certain facts about himself ( like being a Visualize member ) to one person we know of....Lisbon...
Brett Stiles somehow has knowledge of the fate of Kristina Frye....How ? Through his contacts at Visualize ? Ray Hafner is the only known Visualize member among the final seven other than Stiles himself...
Ray is an expert in surveillance....This would explain how RJ is always half a step ahead of Jane...How he knows about the final seven suspects...How he almost seems to be psychic....If Jane is deficient in one area it is modern technology....This would give RJ a needed edge against an intellectual equal...
Remember the video of Lorelei ? This is someone who is tech-savvy...
Maybe he's too obvious...but maybe he's like the Purloined Letter in the Edgar Allen Poe story....An answer that standing in front of our face the whole time...
