tricky, but whilst i don't want this to sound momumentally arrogant (a prefix to a momumentally arrogant statement if ever there was one) but if she was sent to a camp it indicates she is fairly young (<16). and younger kids, particularly girls, change their views quickly and massively depending on who they have decided to idolise... so if she met some bloke at that camp who she fell head over heels for and he is a christian nut she won't appreciate you telling her everything she has just accepted is bullshit.
also religious views and indivualistic by nature, I for instance will never understand someone else's belief in a being they have never met and can't see. so it follows you will not understand what she believes. more importantly if you wade in and tell her its all bullshit she will also not appreciate that...
you clearly need to talk to her, see if they put something in her food etc, but be careful, its one thing to miss your friend who has gone missing, but you risk loosing her entirely if you are too harsh with your questions.
in the end mate you need to give her time and space, this is, yes, extrremely sudden and weird, but she has clearly accepted it, so she needs some recognition of that.
keep us posted though, good luck.
