I have never believed that June 16 story by George--NEVER
Actually, I believe George is the only one who was telling the truth in the beginning. Now he is under Cindy's influence and for Casey's sake-- stonewalling.
I believe, almost certain, that in one interview, he mentions that it was normal on the morning of the 16th, something like "breakfast and all that stuff." He also recalled pretty specifically what they were wearing. It would have been pretty easy to discount this memory if the backpack, say, was still in the house after the investigation began.
Anyway, in one of the document pdf's (15, I believe), the brother, Rick, in one of his emails to CA talks about the neighbors hearing someone in the pool on the 16th. Cindy flatly denies this, and he references a specific portion of some TV coverage.
I've always believed that KC leaves about the time George said she did, returns after determining noone is home, possibly chloroforms K-lee there or elsewhere, then puts her in the pool and finishes the job (using the pool as a ruse). Her intent, I believe, was to simulate an accidental pool drowning, thus the "frantic" calls to Mom -- OMG K-lee in trouble, in danger, what to do, come now. When that didn't work, she panicked knowing that the logical response would be to call 911, which puts her in jeopardy.
She then either hides K-lee in the yard for a short time and comes back (not sure about the forensics on this -- how long for a cadaver dog to pick up scent) or that afternoon puts her in the trunk for a day or two as indicated by the forensics.
As for her disposal, of course, only KC knows exactly when and where, and she's not about to give it up, unless it's to her advantage--at which point the story would be accidental death, panic, couldn't face her parents, blah, blah.
Sad and sorry case -- so reminiscent, pathologically, of Scott Peterson - compulsive lying, friends, sex, others -- all as objects to be used for his personal satisfaction. A robotic, using personality, that because it can't truly relate to feelings of empathy, trust, etc. emulates a normal life, which is anything but normal.
Sorry to be so long-winded, but it sure is a case that gets to you!