Smith killed Kirkland because he found about a secret organisation while investigation RJ. Smith figures that PJ will also find out about this organisation wirh his own RJ investigation so Smith sends the PI to bug the office to see if PJ truly has info on the organisation. When she is caught he figures she is too much of a liability and kills her. This is why her killer has the tattoo. The tyger tyger org members have the tattoos, I dont't think RJ does.
I think PJ lets Ray and Stiles leave and if you look closely there is a car that looks like Smith's car just as Lisbon is arriving at Jane's house (when she crosses two cars and gets beeped at). I think Bertram, Smith, Mcallister and Jane are in this car.
My guess is it's haffner. We can't forget red barn episode. RJ is associated with Vizualise and did you see how Stiles painted the girl with the blood. As RJ admires Stiles, he would have used the writing of the blood in his killings.
This last episode was amazing....although I cursed at PJ for tricking Lisbon (and us viewers). My heart broke into tiny pieces. She was teary and happy about what he was saying and the hug and he played her. Shame on you! :)
