Just read about a case that reminded me of one of the theories about what happened to DeOrr (he wandered off and drowned, and they covered it up).
Reena Williams, 3, wandered away from home in Wisconsin. Her father asked a neighbour if they had seen her, and the neighbour told him to call the police but the father said "We don't need no police". After the father left, the neighbour called the police anyway.
After a massive search, Reena's body was found in a canal 25 yards from her home. Police had to go and find her mother to break the news - rather than helping to look for her daughter, she had gone shoe shopping. The death was ruled accidental drowning. It turned out that there was a long history of neglect, and the little girl was often found wandering. The parents were high when their daughter wandered off and died.
This is the kind of situation where I can imagine parents covering up an accidental death of their child.
They were convicted of child neglect, and the mother got one year of probation. The father got 5 months in jail and 3 years of probation.
http://www.websleuths.com/forums/showthread.php?181819-WI-Reena-Williams-3-Town-of-Swiss-14-Aug-2012