http://www.wlwt.com/news/28919291/detail.html I'm no expert, but the fiance has some very interesting body language in this lengthy interview.
1. Lots of self grooming (calming self, deception, helping him think over a difficult question) especially when he's asked a question that he might not have a ready answer for.
2. Looking down and to the left (deception)
3. Touching nose (classic sign of deception)
4. Adding many extraneous details
5. Seemingly rehearsed answers that he has thought through thoroughly, but stumbling and rambling through other questions
6. Nervous laughter
7. Speaking in past tense of Katelyn
8. Emphasizing how much of a "choice" Katelyn supposedly had in everything going on in their relationship (perhaps it's easiest for him to tell the exact opposite mirror truth about everything)
Anyone care to expound/add more?
This is just my opinion.