How do you know you're not failing Madeleine?

i like the fact people say as a parent i know they wouldnt of killed their child. unfortunately most murders of children are done by family members. this is a fact. just because i as a parent wouldnt kill my children, doesnt mean other parents wouldnt. for what its worth i dont believe they murdered her, i think there's been a tragic accident and they've panicked and tried to cover it up. but even then no one can be sure. good question.