STOP FUCKING SAYING IT IS JANE, THERE IS TO MUCH EVIDENCE TO DIS PROVE THIS THEORY. 

Bertram could be RJs brother - both quoting Will Blake could be due to a shared parent's love for the poetry?

i think RJ can't be Jane, he must be someone who knew Jane before he first started murdering people; my argument is a little clumsy : the RJ smiley looks quite like Jane's face especially the eyes, i believe RJ is someone who's obsessed with Jane and who's killed his family not because Jane mocked him but because of his obsession with him, it's not all, remember what Lorelei asked jane to bring as a present to be his friend : Lisbon's dead body; if RJ really wanted to see Jane's change of heart he could ask anyone's dead body from Jane,the Jane who can't kill a fly, but no, he was more meticulous, he asked for the body of someone Jane cherishes the most, but who would know the person Jane cherishes the most (except Jisbon's fans and Bosco), if he is not someone obsessed with JAne, probably a woman, remember the case where the victims wrote at the wall "he is a man", i don't think it was the victim's writing.

i think some suspects, especially those who were murdered, should be removed from the list: Craig, Dr steiner, Wainwright, bosco and Lorelei; at the mean time i don't have tangible evidence to accuse any one of them but i suspect brenda shettrick and Oscar Ardiles to work for RJ.  
i have a question, why Wainwright was murdered by RJ? was he an accomplice? 

Two things we can take from the latest series is that it is likely that rj is working with homeland. Possibly training assassins. Didn't Lorelei seem a little too professional to be an amateur? And those who claimed rj is pj are know definitely wrong as Lorelei would have killed him.

Enough with the Red John episodes! Since the Red John reveal will not come until the end of the series, they need pace themselves, in terms of the Red John plot line. Too much useless information, too many red herrings, too many inconsistencies with the RJ character, etc. just annoys and alienates the viewers. You can only dangle a carrot for so long before the viewers get exhausted and stop caring.   The writers need self-control; limit the Red John episodes to two per season, unless they are actually going to develop the RJ plot line in a meaningful way...not just add more dead ends and false summits.   

it's definitely not Kirkland. he did shake PJ's hand but Lorelei had no knowledge of this because she was in prison at the time so it must be somebody from the past. Lorelei hadn't been in touch with RJ since she got into prison.

it's not haffner because he is too stupid to pull it off.

it's not brett stiles because despite differences PJ likes him and vice versa.

the most likely theories are actually most unlikely..that would be too easy

the idea of PJ's father seems plausible, however why would RJ go to such a great lenghts to make carnival surrounding at the place of killing Lorelei?

at the moment I still have no idea who RJ could be. I was thinking about JJ la roche as he has the ability to hold power over people (hence manipulating by Lorelei's words) but his physique is not that of RJ.

perhaps we get more clues at season 5 finale..