Check 6 and 8 for further comments.
I read them before I made my own comment. The nine year old girls I know (and I was one, myself, and a cagey one at that) could easily be intimidated into being quiet. She would already have come clean by now after seeing the worry and fear of her parents, and being intensely questioned by police.
If she left in her red pajamas, she was abducted.
She's dead by now.