Re: How can they proceed?
Well, the girl will definitely be in a mental institution for years to come; however, their babysitter should be charged with involuntary manslaughter. The care of the children was her responsible for their safety, and she failed this responsibility.
I do believe, however, that the 5-year old should be charged with voluntary manslaughter. While she did not wish for the boy's death, her actions and statement show she did wish him harm. And yes, they can charge her with murder.