By considering only the last episodes on S5 there is only one plausible explanation for Red John knowing about Patick's "happy memory" and killing it.
First of all consider that Patrick said he never told anyone about that memory, so anyone that knew about it must have got from Patrick in some other way (written in a piece of papper on a notebook for an instance).

For all I know Kirkland is not likely to be Red John himself, also it would be too obvious.
But Bertram and Bob Kirkland on previous episodes have showed mutual respect and complicity. Therefore we can consider that all the information Kirkland got from breaking into Patrick's "office" is also available to Bertram.


One fact was still without explanation even with the end of the season: why did Patrick smile on episode 19 when he returned to his office and noticed that someone had broke in? Why wasn't he upset even for a second?

In my opinion Patrick planted the information on his room about the memory (to track the availability of his research to someone), so Kirkland got his men to run the search in Patricks room and passed on the information to Bertram, including a false (or not) one about a "happy memory". That explains the reason Patrick was not nervous when noticed someone had broke in and had access to all the sensitive information on his room. It was the plan from the start just like we see in several episodes.
The only two person that clearly had information on that room was Lisbon (when Jane let her in) and the men who stole information to give to Kirkland.
Red John can also be more than one person, still I believe Bertram is more likely.

The end of series 3 the only person who could have set up the fake John encounter in the Mall would have been Bertram.

Apart from Stiles & Bertram it is hard to see any of the other suspects having the charisma to manipulate their acolytes. Both are also follicly challenged making it easier for Hawker to confirm that Carter was not Red John.

If the producers have carried this through and not just made the suspects up  at the end of this series Bertram's build bothers me being larger than the figure that recited Tyger to the captive Jane and passed Rebecca in the corridor - unless he always gets his acolytes to do the work.

I basically have 3 questions for the people who are more observant than I am and then I'll give my thoughts on who RJ is.

1. I think Lorelei mentioned it in the video, and I am wondering, how exactly can RJ know that Lorelei told PJ about the hand shake?

//I don't think she told RJ, because it was a "mistake" in the first place, she said it without thinking, so what? Can we say that she specifically realized such a small detail and even told RJ about it? Also, he was mad about it. Given that he probably knew before he caught Lorelei. In order for him to be mad, he would need something solid to make him believe that PJ will actually use that to narrow down a list or something.

2. How come all of RJ associates suicide, are too loyal to him, and would do anything for him? I don't understand, they remind me of spies who die for their country or something. How can one man have so much influence? 

//Who can have so much influence, power, information, computer skills, and unlimited $$ at the same time? To be honest it only sounds like a "religion" in a sense and it's branches with people in all these places. Visualize has to be definitely connected RJ. The only man who can probably do everything above is Stiles, but he is too old in a sense.

3. What exactly is the connection between the victims of RJ? How do we define him as a serial killer?

Most of his victims are people who pissed him off or something, or people who he killed to make PJ mad. Besides that, how are the victims connected? What does he go for?

//I know he is "famous" for killing some women or something, but I don't recall ever in the series of someone mentioning a pattern or something b/t the victims. It is interesting to me that the only similarity is the setting and the smiling face. I want to know if there are certain victims that he kills.

This is the reason I chose Brett Partridge for now:

He was there all along, and he is the only one from the list that sounds like RJ material. Of course he has a lot of help, and I believe he has someone inside PJs team. Also, all of the 7 suspects are connected to him as well.

The main reason I wrote this is just to see your comments about the questions I have. 

This are some of the clues the executive producers of the show (Heller, Gable, Szentgyorgyi, Gable, etc.) have told us about Red John.

- It is very possible that Red John is more than one person. (https://twitter.com/mentalistwriter/status/114527763079245824)

- It would certainly explain a lot if Red John is or was a Mentalist. (http://twitter.com/#!/mentalistwriter/status/114528098116042752)

- Red John has been visible in prior episodes. You’ve got to look for him like Waldo. (http://twitter.com/#!/mentalistwriter/status/114530384280158208) [This comment was made before season 4 premiered).

- Jane is not Red John. (Bruno Heller in an interview)

- "Season 6 apparently they’re going to catch Red John. Seriously, that’s what I heard. I don’t know if I’m allowed to tell you. I don’t know who he is. But apparently we catch him!" (Amanda Righetti in an interview.)

- [Question: Will you cast Red John next season? (this was published before season 5 premiered)] Will I cast him? He might already have been cast. You might already have seen him. (Bruno Heller in an interview.)

- [About the list of 7 suspects] Yes, we can trust that list. As much as much as Red John has been one step ahead, Lorelei Martins’ intervention changed the game. So as much as Red John is trying to play from a position of strength in reality Jane has gotten a lot closer. This last episode of the season really sets us up for next season: The hunt is on, no messing about.

- [About the season 5 finale] This season has been about Jane digging into the notion that it’s not that Red John could be anyone; it’s that Red John is one of a very specific set of people that Jane is uniquely qualified to investigate. The finale is going to pay that off in a way that will completely change the hunt for Red John. We are going to know some very specific things about who he might be. (Szentgyorgyi in an interview.)

- [Question: The arrest or the death of Red John will determine the end of the series?] For me, yes. There will be no follow-up or spin-off. (Bruno Heller in an interview.)

- [Question: Are you spreading clues about Red John's indentity?] Yes. But we're also sneaking in some false clues. Fans will have enough elements to find the solution before the end of the last episode. (Bruno Heller in an interview.)

- [About revealing RJ's identity, before season 5 premiered] Sure, if season 5 we just opened a door and said “tah-dah!” and it was some mid-range actor, that would be disappointing. The trick is going to be — and this is coming — bringing the audience along and making them second guess themselves and ask, “Is that him? Is that him?” Red John ultimately is just a man — whenever you see the great criminals reduced to the flesh it’s sort of disappointing. I have two seasons or so to make it come true. [Joking dryly] I can guarantee that people will be disappointed. (Bruno Heller in an interview.)

That's all I could find so far. If you have any more clues from any of the show producers, please post it in the comments.