List of people who disappeared mysteriously: pre-1970
Most creepily:
Bobby disappeared during a fishing trip. A child found in the custody of William Cantwell Walters of Mississippi eight months later was ruled to be Bobby Dunbar by a court-appointed arbiter, and Walters was found guilty of kidnapping. The child grew up as Bobby Dunbar, had four children of his own, and died in 1966. In 2004, DNA tests proved that the child found was not related to Bobby Dunbar's brother, Alonzo.
In other words, some rich family lost their son, stole a poor family's son, and blamed the father for kidnapping.