Nancy Guthrie, an 84-year-old missing woman, is the subject of a kidnapping investigation with a ransom demand of eight million Australian dollars in Bitcoin, due by 11 a.m. Arizona time. Investigators are working to authenticate a ransom note sent to a local TV station while conducting searches including a septic tank on the property. Former FBI agent Mike Harrigan discusses the challenges of verifying ransom demands and the difficult decision families face about whether to pay kidnappers.