Sorry that I am so far behind you all! I have only just known about this case for a few days! I have just watched this video:
http://www.kshb.com/dpp/news/region_missouri/northland/lisa-irwins-parents-to-speak-with-today-show
OK, for starters, I'm not at all comfortable with Jeremy Irwin's body language. He looks nervous and awkward, and I feel that a lot of what he and (mostly) Deborah said in this interview was unnecessary, such as the part where they were thanking people, like the police department and the FBI. IMO it was said by them to take the focus off what they know that everyone is thinking, which is that they know what happened to Lisa. The question asked of them was not 'who would you like to thank?' so I think they intentionally went off track a bit. When Jeremy answered questions, he sounded completely unconvincing, and watch his hands! Nervous fidgeting. Classic lying sign, I think.
Deborah's crying abruptly started and seemed to stop just as abruptly. This interview was given mere days after their daughter was supposedly abducted. How would any grieving parents NOT be in a million pieces at this point? And why are they both sitting that way? Not leaning on each other for support and not comforting each other, except when she put her hand on his lap? It's so weird. I'd love to see a body language expert's interpretation. I think it's too dangerous for them both to share the questions and interview equally, which is why she is the one doing most of the talking. She butted in at one point and took over from what he was saying. I just don't trust these two at all.
Also, at the very end when the interview is over, watch Deborah's shoulders visibly relax. I see that as her breathing out a huge sigh of relief that the charade is over for the time being. (The top video on the page - there are 2.)
They seem to have said too many times 'we don't care about XXXX' and 'we're not angry'. Who would think to even say that at that point in time? I think they have thought too hard about what to say to sound genuine, and they failed. Badly.