I've always suspected that they(CA,GA,LA) had some ideas about where Caylee might be ...after all,I think they wanted her found(probably suspecting that she's dead),they just never admitted it in public.Somehow understandable....
I've had a nagging thought for awhile... Remember the first time TM came to search and CA insistently dragged him away on a false sighting for a live Caylee? He left the area and went with her. I remember feeling so frustrated that he would waste time and placate her, but he had to because it was so early on. I think this was the day he was near the spot where Caylee was eventually found. I think CA knew very early on where the baby was. IMO.
ETA: I don't recall the exact timeline but maybe TM never got back to that spot because the rains came?