Sheriff Mcallister is Red John.
I support my theory on the following facts.
1- In the scene where she saves him and recited the poem Tyger, Tyger: approaches him quietly, without noticing Patrick.
2.- Also goes to him quietly, in the 6x02 which saves him a second time, without noticing on two occasions.
3- In this chapter, we show that cross quiet until the pigeons appears.
4. - On the other hand, the actor who will make Red John, in chapter 8, he looks like him young.
5. - After reading the theory on a Blake poem and see the description http://www.whoisredjohn.com/See-a-theory-Red-John/7453 I am convinced: Old John with white hair
6. - Sherif is connected to Bret Stiles may be his brother or Partridge, in which case the 666 make sense.
7. - The three dots SPOILER Also can carry religious meaning, Representing the holy trinity.
8.- finally when when he killed a accolite in CBI offices he looks dress as a sheriff.
9.- When the list is given the only person who is not called for his name is sheriff