If you stop at 15sec and you take a closer look the hair of the subject you can notice that is not completely bald and there is a small line of hair in the middle of the head. You can compare that with Gale Bertram's head and see that it doesn't match, because Bertram exept for the back side of the head is compleately bald. 
Sheriff Thomas McAllister instead fits perfectly that fisionomy. According to this you can now add the fact that both McAllister and Red John wear the same jeans and jacket. Plus there is a pidgeon sitting on the statue right after Patrick shot Red John. 
McAllister said clearly he hates that things (pidgeons). The usage of that is to let Patrick realize which is Red John's phobia and finally put all pieces together.
The fact that McAllister is Red John fits perfectly. He lays low and living in the Napa county is able to move freely. He is part of Blake Association because is a cop, obviously. He managed to control Blake's members thanks to his ability to manipulate people. McAllister knew what Patrick Jane wanted in the very first moment he received the phone call. He placed the bomb and knew the exact wayout of the area in order not to get hurt.
He said to Patrick he is not Red John because he knew he could play the card of the tattoo and had the bomb as a backup plan. He gained time for the bomb. He licked his lips because he was really nervous. He was the only one not losing the head when Patrick took out the shotgun (he just said "take it easy Patrick", again to gain time for the bomb). Bertram tried to reason with Jane "you've gone to far", Smith tried to pull put the gun, prevously Haffner tried to leave the meeting, Stiles mocked Patrick but McAllister was the only one who stayed calm and waited.
McAllister hunts everything with a face as he said. I believe he hunts animals to keep his need to kill a little under control, then sometimes he just follows the flow and becomes Red John.

Sequence shown in the Sneak Peek->FBI breaks into Patrick Jane's place at CBI and found nothing-> Patrick goes visit the grave of his family -> FBI gets Bertram -> Jane confronts Bertram -> Bertram says he had to meet Red John in the church so they both can escape -> Jane puts the gun in the church's bench -> the FBI is at the graveyard waiting Red John and so are doing the former CBI agents -> McAllister is spotted at the graveyard by the CBI agents who doesn't inform the FBI but Patrick instead -> Patrick runs with the car at the graveyard -> scene with FBI and CBI holding guns each others -> Patrick touches FBI agent who was previously ipnotised -> Patrick reaches the church before Red John -> Red John thinks to meet up with Bertram and finds Patrick instead -> he says he won because he is stronger than Patrick and in that faceoff  Red John clearly wins -> Patrick shots Red John -> Patrick notes the pidgeon is distracted and Red John escapes -> scene in which Patrick runs after Red John in the graveyard -> scene with McAllister breaking the window and Patrick right Patrick runs after McAllister -> McAllister reaches a calm place in the park, is wounded and suffering and couldn't escape anymore -> Patrick reaches him, Red John is laying on the grass, Patrick takes his time and looking Red John straight in the eye, shots him. Then there is the end of the season.