My theory, for what it's worth: Nancy wasn't kidnapped for ransom. She was taken by an obsessed fan of Savannah's to inflict the maximum amount of pain on her. This would explain why the "kidnappers" have not contacted the family and there's been no verified ransom demand. She wasn't taken for ransom, she was taken to hurt Savannah, and how can you hurt someone more than by taking someone they love away from them. Obsessed fans have done things like this in the past... Remember John F Hinkley, an obsessed fan of the actress, Jodie Foster? Hoping he would get her attention, he attempted to assassinate President Reagan.