If the motive is financial and the ransom demand now clearly a bust, and Nancy is still alive, and the perp is as intelligent as it seems (sometimes), then why not:
1) have mom or dad or spouse or child setup an interest bearing trust
2) confess to them
3) they turn him in
4) they return Nancy
5) collect 1.1 million
6) serve 15 years
7) retire
This is a big reason I no longer think she is still alive, because surely if he tried to scam 6 million dollars from them he'd also try to scam 1.1 million that would probably be worth 6 million in 15 years, no? And heck, if she was still alive he'd probably get a plea deal for half of that if he plead guilty and filled in the details. So what's to lose?
Personally, I'd rather spend 7-15 in jail than 7-15 always looking over my shoulder.
JMO.