Reasons for "Michael" Kirkland, Bob's twin brother.

1.) Loreli said, "I wonder why the two of you didn't become lifelong friends the moment you shook hands."  To me this implies they shook hands a long time ago, i.e. probably while Patrick was still at the carnival.

2.)  Bob/Michael Kirkland told Lisbon while drinking coffee, "We moved around a lot, for my dad's work and then mom's.  I like to say we grew up in America."  What profession makes you move around a lot?  Working at the carnival!!!  I think "Michael" Kirkland shook Patrick's hand way back when they were kids at the carnival together.

3.)  While drinking coffee with Lisbon, Kirkland calls Lisbon "Teresa" just as Red John says to Jane, "Sorry Patrick.  Teresa can't come to the phone right now."

4.)  In episode 5-18, Kirkland asks Lennon "Do you recognize me?  This is very important."  Why would this be Bob's only question to Lennon if he were searching for his brother?  All that torturing and interrogating of the fake suspects on Jane's list, he was tenacious and thorough.  If Bob Kirkland was interrogating Lennon, this would NOT be his only question.  "Michael" on the other hand would only ask this one question if he were Red John and wanted to be sure Lennon did not recognize him.

5.)  Just after killing Lennon, "Michael" Kirkland refers to Jane as Patrick.  "Patrick. It's terrible.  His heart just gave out..."  Red John ALWAYS calls Jane by his first name, Patrick.

6.)  None of the other suspects refer to both Lisbon AND Jane by their first names.  "Michael" Kirkland is the only one who does.

7.)  When Loreli is reading off Jane's suspects in Red John's video, the ONLY person she refers to by an informal nickname is "Bob" Kirkland.  Everyone else is referred to by their full, formal names.  Who would call Robert Kirkland, Bob?  His brother, Michael! :)