I think it's pretty obvious Heller is lying about many things. He said Red John is someone, who has been there from the start. On the list of 7, only Partridge and McAlister have been there from season 1.
So, Partridge is dead, Sheriff has to be RJ, or is he?
Bertram was introduced in the third season and that is not "from the start" in my opinion. Smith came into the series 2 years later in season 5. Then there's Kirkland, who has been introduced to us last season. Stiles has been there since season 2, if I remember correctly? Haffner also became a part of the show in season 4.
The list itself doesn't make much sense then. And I honestly don't believe it. I still think, RJ will be one of them, but Heller wants us to think that the list is fake.
My favourite from the start has been Sheriff, because he has been there from the start, smells things around him extremly good, is a great shooter and walks like a hunter, quietly. Also, his job wouldn't limit him doing all the killings.
But I'm not sure anymore. When he revealed the three dots tattoo, Patrick aimed the gun at him and he said "It's not what it looks like, I'm not Red John." I don't know if I think of RJ too highly, but RJ wouldn't said that. He wouldn't lie to Patrick's face.
Bertram looks like a good option right now. He didn't say a single word when he revealed the tattoo. He always carefuly chooses his words when he talks, we could say manipulatly.
Some things we already know also point to him. Heller said at the end of season 3, we would see Red John in the season finale. Bertram was there with Patrick, but left before the whole PJ - Carter dialogue began. Everyone thought Heller had Carter in mind, when talking about you're going to see Red John. What if he meant we're going to see Red John because Bertram was there?
Bertram also said in the first episode of season 6 to Lisbon and Patrick: "I am many things to many people." I think this sentence has a deeper meaning and we shruged it off to quickly.
Also, the first impression is the most important one. Patrick didn't feel good when he met Bertram. That is something to point out.
It could honestly be anyone, except Smith (IMO he joined the show too late) and let's hope we get an explanation about everything we want to know. Because there are a lot of things I am curious about!