1. His voice matches that of the masked villain during the slasher flick
2. His mannerisms/actions mirror that of Jane
3. He has the resources
4. He wore a bright red sweater in "Red Hot" season 3

He is the only guy who slept with Lisbon.

Mashburn has the money and the time to do everything that Red john has been able to do.
I think Currie Graham has the carisma to pull  off the acting.
I hope it isn't Brett the Guru, too obvious.

Red John is a cult leader. Is an international criminal. (example he is linked with at least 1 death outside of the United States.) He has many followers. He is just a man, but he has lots of money, power, and influence. He is not on a CBI's or even FBI's salary.

My belief is the Robert Kirkland is a good guy. He is tracking international criminal's, and RJ and Volker are. My prediction is Robert Kirkland is a deadman walking. Red John's associates will get to him, and the CBI will have the case back.The only problem with mashburn: is his influence and following..I don't see it. Could be Ellis mars also.

 Lorlei told Peatrick that she thought that he and Red John would become "BFF"s.  Walter is rich, the right age and dPatrick liked him immediately

I found another clue on Mashburn, in addition to those of the user IKnowWhoRedJohnIs.

Renfrew in 1x11 write He is Mar on the wall. Could be He is Mashburn, but could be also He is Marin (county) a shorter way to say: He's from Marin.
Mashburn live in Marin County.

One theory I have not read about and seems more plausible is that we do not know for sure if we have actually met Red John on the Mentalist. Heller said that we MAY have seen Red John already. We ASSUME that it was RJ who killed those 2 kids trying to kill PJ. We have already seen that Heller puts several things in different episodes that makes you believe someone is RJ and its not especially on the one where Tim Carter says he is RJ. One thing that is extremely telling is when Bruner Heller stating that Red John was Like Moriarty from Sherlock Holmes. It all makes perfect sense. Moriarty used people like pawns never doing any of the dirty work. Its obvious that Brett Partridge is the guy that kills those two kids the voices are identical. It doesnt him make him RJ. RJ has people all over CBI and different forms of government. There is still one person we dont know about inside who gave away his plan to RJ when PJ supposedly fell apart. The guy in the limo has to be someone extremely powerful. He is high up on the food chain and it cant be Partridge that makes no sense. The guy in the limo could have been RJ but who kwows he said two words. The person that killed Bosco's secratary could easily have been one of his inside people maybe Partridge. I think Heller does all of this misdirection to really keep people off who it really is. I think the ONLY thing that is really definitive is the blind woman knows RJ and that is it. Heller can easily come in and show that other people did this other stuff. Remember RJ is very very smart. He is smarter than Jane and has more connections that anyone. Also we know definitively that RJ has a connection to Visualize and Stiles HAS to know how RJ is. How would he know where K Frye was? Why didn't PJ say hey how did you know where she was unless you are RJ so it rules Stiles out. He is not some pyscho killer. I think Stiles knows who RJ is but cant say anything or he will get killed. Assuming that RJ has been on the show which is not even a for sure thing Mashburn is the only prominent actor who is old enough, smart enough (he acts stupid but is not) and has the money and connections to do it. The actor that plays Mashburn has the actings skills to really change things up. People that say PJ is RJ really overthink things. There are at least about 20 things that make no sense when you say PJ is RJ. Plus the show would never fly in syndication. The entire time he is chasing himself give me a break. Also the episode where the guy rights out He IS Ma. I would bet it was supposed to say he is Many or if it is Marsden it would be Marsden. I think think there is better chance that RJ has never been on the show yet. Like I said I think when Bruner Heller stated that Red John was Like Moriarty it makes perfect sense especially if you know about Moriarty and how he works. There is so much misdirection just like the list that PJ makes. The first person is Partridge and it say macabre which refers to death. I think he is one of RJ pawns but not RJ. Another person on the list is Mashburn. Again there are still some things we dont know about like where is PJ father. I have no idea if that if that makes a difference and how did PJ mother die?? Just some thoughts.