They left their home’s lights on, leaving behind their IDs, money, and Billie’s medicine. Mary and Billie had known each other their whole lives, growing up and graduating high school together in Missouri. They had successful careers (Billie in engineering and the Air Force, Mary as a teacher) and a son.

However, by 2009, both were seriously ill. Billie was stressed caring for Mary and even told their son it would be better if they weren’t around. Police and family fear they are dead, with one theory suggesting they might have accidentally or deliberately driven into the Missouri River. Unfortunately, there’s not much evidence, and the case remains a mystery.