Red John is a persona or a construct created by Brett Stiles, not one particular person. The Visualize religion is a cover for a CIA clandestine operation to develop assassins using post-hypnotic suggestion, narcotics and psychological conditions (i.e, phobias) as tools.
The subjects of the operation are drawn to Visualize and if they are suitable, they are brainwashed and conditioned to believe they are Red John.
At this point their suitability as assassins is tested by various targets to which they are assigned.
The idea is that clandestine operations can be executed by subjects who are not aware of what they are doing and have complete deniability even under torture.
I deduced this answer from the following observations:
1, Brett Stiles has a long association with Red John dating back to the first happy face on the barn.
2. Hypnosis and psychological susceptibility is a frequent theme in the series. For example the man who drags in a body to CBI believing it to be a sack of potatoes.
3. Stiles has friends in high places, throughout law enforcement. They are not touching him because his program is sponsored by intelligence agencies of the government. This is idea has parallels in real life such as the MK Ultra program from the 50s and 60s (look it up, its scary!).
4. There needs to be a trigger for the post-hypnotic suggestion. It is Tiger Tiger.
5. At least two of the suspects have phobias (pigeons, heights or spiders). This points to a psychological susceptibility.
Its not possible to determine, which of the seven original suspects are 'Red John' but my guess is all of them, and probably more (Roy Tagliaferro, and all the characters who have said 'Tiger Tiger'! ).
Hope you like the idea, Happy to discuss it.
