Let's think about who would have wanted to bug the office, I think it's very important.

1. Bertram is out, he could have bugged it himself anytime.
2. Haffner is out, he was in the office a couple of times in that episode, could have done it himself.
3. Reede Smith: I refuse to believe this nobody is Red John, if he is, this show will have the lamest         ending in the history of TV shows. He is a random stranger who nobody's ever heard of before season   five.
4. Stiles could have done it, but let's be honest..He is almost 80, he is dying, the FBI is looking for   him...It just doesn't look like it's going to be him.
5. Sheriff: He could have done it.

What we learn from this is: Whoever Red John is, the other tigers don't know. Because if the sheriff is Red John and the others know, he could have asked Bertram to bug the office, no need to bring in a silly private detective. (same for Smith)

So I think it's either the sheriff, or someone we think is dead or not on the list.
It cannot be Bertram or Haffner, they could have bugged the office themselves. For me it also can't be Stiles and Smith for the reasons I mentioned above.

It's the sheriff, or someone "dead" or a person not from the list.

I hope they explain what happened to Kristina. and why red john didn't kill her same with Lisbon. I have feeling she is probably Red John's sister. Explains why she knows a lot about who died and will die.Jane said on the TV show about red john living with sister or mother and a lemon tree by the house. could be a guess he did or could be true.

Did anyone notice in the scene lisbon gets zapped after she sees partridges dead body that the only way for rj to get her was from the window behind her ? Is that a clue ? Cuz her back was to the window and if u see there was no wherre else for anyone to be...weird.