i know this is a big guess as much as i thought it is Bob kirkland or Brett partridge
know watching a clip from season 5 epsidoe 21 when lisbon goes to speak to the guy at the end and finds out he cant talk... she smiles when the mother tells her the tounge was never found but then........ when the guy who cant speak, mumbles (or something like that) "its red john" lisbon looks up at him in shock and then he says it again.. "its red john" or so it really sounds like it.... i was very surprised and shocked of how similar it sounds... lisbon is one of my favourite characters but can defintaley fit the identity of red john if you think about it!!