I have always suspected him. After the 2nd episode this season with Lisbon in the hospital and the 1 on 1 Jane had with Kirkland last nite that mentioned someone who was persuasive and quasi-religious I am 90% sure that it is him.
The only other plausible explanation i can come up with now is Kirkland's twin brother. Also lost in that 1 on 1 was were Kirkland mentioned that his brother was sadistic and twisted. Loralei could have seen Kirkland and Jane together and not realized that the Kirklands were twins and assumed it was Red John.
