@candacecanfield,
As a non-lawyer I would say that unless he is totally unfit a court would more then likely will in the end allow her to live with the parent of her choice.
Assuming you now had legal custody you can of course give him all kind of headaches and demand that the cops return her for the moment however she can always run away and that would be very bad indeed and in the end if he willing to take you to court and is not totally unfit he will win with her support.
Note once more I am not a lawyer I just play one on the net, however I would bet that a real lawyer will tell you the same thing.