Just a few thoughts ...

The most recent murder:  With regard to RJ, this last murder seems very rushed and sloppy (not quite the methodical, fear-inducing type (to Patrick) we are used to seeing and the victim is left alive ... perhaps on purpose?).   In addition, we did not see the trade mark smile face.  Was this RJ?  I'm not certain it was.

The 3-dot Tattoo:  Not having too much knowledge of tattoo's, I did a bit of looking into them.  Although this particular tattoo can have a few meanings, one of them is religious in nature (trinity) ...

Stiles:  When Lorelei says that Jane is "just like" RJ and she is surprised that they did not become life-long friends the moment they shook hands (in the context of Jane is manipulative), the first one that my gut instinct went to is Stiles.  Of course, just like most on this blog, I came up with a list of why he couldn't be RJ ... he is too old, etc.  However, I still think he is absolutely the most "like" Jane and I cannot dismiss him.  This is not to say that he is necessarily the one to actually carry out the murders, but he certainly has the ability to manipulate people and has financial means as well.

McAllister:  In the episode where RJ saves Jane from the teens about to kill him, did you notice the boots?  They definitely remind me of something McAllister would wear and he even mentions in a recent episode about not being able to go up the ladder in steel tipped boots.

Haffner:  He has everything on the list to be RJ in terms of physical characteristics, etc., and he obviously cannot be ruled out, but something tells me Bruno Heller might be playing the audience ...   This is not to say he couldn't have a major connection; however ... like RJ's son perhaps?

Reede Smith:  I would not be happy if RJ turns out to be Smith and do not necessarily think he is ... but one thing I have noticed though is how many times Reede is smiling a lot in the recent episodes ... very strange, I do not remember this in the past episodes so much (I'll have to re-watch them... it kept reminding me of the round smile face that RJ creates.  He also seemed in charge in the meeting with Bertram and McAllister (he tells Bertram "it's your job to know," with regard to keeping tabs on what Jane knows.  In addition, he easily kills Kirkland with quite a bit of vengeance (6 shots to the back).