It's Lisbon.  The person who recited "Tyger Tyger" to Jane at the end of season 2, when he was tied to the chair, was a woman.  I base this on the walk and the way she put her hand on his shoulder.  The only person that Jane told he was going to the building was Lisbon.  In the scene immediately before Todd Johnson is set on fire in the room at CBI headquarters, a person is standing looking in at him, and that person looks like Lisbon.  At the end of season one, the deputy starts to name Lisbon right before he tries to kill her.  Then there is the cast on Lisbon's arm, the fact that she was visibly jealous of Kristina Frye and Lorelei.  It is Lisbon, right under Patrick's nose.