I think there have been some great posts already that I agree with.
Just want to add:
1) Although in hindsight we know that Kyron left the school without being seen, I don't see how anyone could plan to get away with doing that. I don't think TH could be certain that no one would witness them leaving together and remember that. It makes me feel much more that this was an opportunistic crime and the responsible person just got lucky that it wasn't reported for so long. NO ONE could have predicted that. I think he thought he might have 45 min- 1 hour before they reconvened in the classroom and just got really "lucky."
2) Kyron's friend TP's story has a ring of truth to it. Not like a videotape of what happened, but the seed of truth in the center skewed by the perception of a child. It may not have been word for word exactly like he said, and there may have been some follow up he missed, but I do believe that the chaperone saw Kyron and then didn't when they reconvened in the classroom. I just can't imagine a kid coming up with that out of whole cloth.
3) I have seen NOTHING that makes me think she's guilty, and I've seen LOTS of stuff that seems perfectly innocent that others have tried to spin as evidence of guilt. The captions under the fb pics - totally normal in context. The cell phone pings - never confirmed, just a rumor on some unmoderated comment board. Not going to the talent show - never confirmed that Kyron had any significant part and the baby was probably sleeping. Going to the gym - maybe not my thing, but I've known several people who have done similar in life and death situations. This interview with her friend - I have done multiple, hours long tapings with CNN and others only to have them edit it down to 90 seconds and totally miss the point.
Also...
I can't judge that if LE has said you absolutely CANNOT help with the search b/c it could be misconstrued if you actually find something. Plus, not wanting to leave the baby after all of this.
I can't judge if LE has said it is in Kyron's best interest if you stay as far away from the media as possible and go about your normal activities. In that case, I would do as much as I could that they recommended, hoping against hope that I would follow the checklist and he would come home. As other posters have pointed out, NONE of the four parents have been accessible to the media, which makes me think it was a strong recommendation by LE, but only one is being judged for it.
I can't swear she didn't do it, and I've been wrong before, but I haven't seen a single thing to convince me.
ETA: I have included some rumors only for the sake of telling why they don't sway me, and clearly stating that they are rumors. I hope that's okay!