Sallies my gut feeling, in the case of missing Caylee Anthony is that the mother, the Grand mother and father, plus the great grand parents, all know what has happened to her, but they are staying strong, so no one will have to do any jail time; the brother is out of the loop.  

    Arvin looking at all those pictures, considering all the misinformation, something unintentionally and in rage, likely happened to Caylee.  Plus, Casey's mom is protecting her daughter.  Casey's life style seems far from that of a nurturing mom, and, hard as it is to believe, some strippers are better parents from what is suggested, by some, in society.  Who knows what has happened to little Caylee?  Maybe Casey is protecting some man that has hurt Caylee, by some derelict and aberrant act.