I wish that Frisson was able to elaborate on his theory, perhaps he/she will. I'm going to be curious as hell when the trial starts. The Feds seem to have one other person locked away indefinitely, so if there is another player, he would be my guess. I really am doubting that there is another involved however, the state hasn't mentioned anyone else and the community was never put on alert. Plus, the smile in the courtroom tells me that he is guilty and that EA knows that the only power that he has left in his life is to hold the information of CM's location back. He may hope that he can negotiate with it or gain some type of pleasure in punishing CM's family.
So, that location seems reasonable. I also think that she may be in the most likely spot on Earth, like C Tennyson. My guesses would be in a green space around Shops at Legacy or the huge green space close to his home, Oak Point park/Bob Woodruff park.
I wish I were able to as well. I just think there is more to this story than has been put forth so far. There are some pertinent pieces....details missing (imo) Does that help?
Justice for Christina.