As I have stated in another post, they need to look at who are close around the family and by doing that they will find out what has happened to the little girl.

We feel strongly as it has happened to an innocent defenceless child of 3. But things like this happened in many poor 3rd world countries everyday but there is nobody willing to help their parents as they are poor. But you are right sometimes most crime is done by somebody that is actually known to the parents or even the parents themselves. I still remember the case of the Bennett girl who was killed in her own home and nobody is the wiser. So who could go in and out of the house so easily and not be detected? If the parents believe in magic, they can get a reliable shaman or high priests to call the body out. I have seen it done many times here in Asia for drowning victims (an uncle who drowned and whose body was held captive by sea spirits was found after my aunt asked a bomoh - a islamic shaman to help her). Unless of course the parents were the real culprits!