I was watching the pilot and the focus on the hands shake between the Dr and PJ was like the light in the dark.
He's a psychologist, he's smart and has a soft voice.

He's on the Jane's list of 7 too.

http://thementalist.wikia.com/wiki/Jane%27s_List_of_Suspects

Just a guess. But look at the pilot and think like you would finish with the same guys you started.