I definitely think it's DC. He is potentially the most explosive witness that could come forward. Who knows what he saw, heard, and did in the Anthony home and in trying to find Caylee's remains.
And when you think about it, he's been left out to dry. Baez hasn't paid him, I'm not sure the Anthony's ever did (correct me if I'm wrong here), and it seems like he's been pushed out of the Anthony inner circle as well as the defense inner circle. You'd think they'd learn after Padilla to keep their friends close and their enemies closer, but yet again, he's been left to deal with the SA leaning on him on one side while the other is telling him to shut his mouth all by himself as far as anyone knows (well, with only his lawyer for help).
I think he finally got tired of all this and decided to come clean. The A's definitely prey on people they can manipulate to do their dirty work and then discard them and defame them when they don't need them anymore or feel like they have been betrayed. I see where Casey herself gets that attitude from. It's why she won't have any character witnesses other than her mom, dad, and brother at the trial.
And I can see the SA wanting more time to verify what he says and what evidence he may have because even they know that the defense and the A's will want to tear DC to pieces and destroy what's left of his career. We already know the A's have no problem turning on anyone that they think they can point the finger at for Caylee's murder. I can see that as a definite reason to NOT have the defense there and NOT release this potential bombshell information.
Also, I agree with what was said earlier in that they might be deciding to go after CA and GA and possibly Lee for obstruction and maybe even disbar Baez (at least get him off the case, therefore possibly giving the 15 months time for a new lawyer to take the case) because of what testimony and evidence DC can possibly offer, and the SA would definitely want more time to investigate that.
I just don't think GA or Lee have the stones to go against CA, so I can't see it being them. I don't really think Mallory knows enough for it to be explosive information. I think the Milsteads just want to hide and get away from this whole thing. SA has known for a long while who the father is, and that doesn't really have much to do with the case anyway since he's never been in Caylee's life and may never have known he had a child in the first place. It could be FBI evidence, but they say it's "NEW" information, and they've known for awhile what the FBI has, at least most probably by phone. It could be someone totally new, but it's been what, a year and six, seven months since the murder?
Who could possibly come forward and offer anything more explosive now other than DC?