"Come and get me, Mr Mike, make them come and find me"...
To be honest mike I think your emotions have overtaken the facts. Maddie does not know you from Adam. If she was crying from the grave then surely she would be crying for mummy, or daddy.
Sadly I believe that Maddie is dead, but do not think that her parents had any part in her death. I do think that it was stupidity to leave the childen alone, but they must have thought it was safe, as they were close at hand, and were making regular visits to the house.
You are not posessed with magical powers[ I think], so we can only have assumptions.
All this Mr Mike does nothing for me, though I would be happy to be proved wrong.
TBH I am more interested in springing Jeremy.