Is this a good opening for my nieces mystery story?

No, it isn't a good opening. It doesn't make me believe that this is a real person, or a real event - but my curiosity is piqued. Not by the story, but by the fact that you are asking for a critique and suggestions. Why isn't your niece looking for help? It's much easier to deal directly with an author than to go through a third party - or is this your story and you just don't want anyone to know about it? We've had bashful authors on line before... =)