Ask yourself this: Why didn't Red John kill Lisbon yet? Or, why hasn't Red John killed Lisbon before? He always talked about killing the people Jane love most. 

A logical reason would be Ray Haffner, who also has feeling towards Lisbon. He is the only one out of the 7 suspects who knows Lisbon. 

He has connections,power and is a member of Visualize. He also fits the description of the recording in 6x02. 

Are there any faults in my theory? Let me know!

Roman