Their daughter-in-law found their house a week later with unopened mail and milk. The door was unlocked, but Mary’s purse (which she always carried) and some medicine were left behind. Only their beige 1958 Chevrolet (license plate 225-910) was missing.

Frank, originally from Czechoslovakia, was a mason, carpenter, and farmer. Mary was from Nebraska. They’d lived in Wilber since 1957, a town with a large Czech population. Mary enjoyed gardening and bingo. They had suffered previous losses: Mary’s son from a previous marriage died in 1959, and their daughter died of polio in 1960. Only their son, Frank Jr., survived.

Mary’s health was failing in 1973. Frank had recently said he didn’t plan to travel anymore, though he often took Mary for short drives. Oddly, two weeks before their disappearance, he bought a Kansas-Nebraska road map.

Police and Frank Jr. believe they committed suicide. The theory is Frank drove his car into a flooded sandpit because he couldn’t cope with Mary’s declining health and didn’t want to put her in a nursing home. Searches turned up nothing.

Seven years later, they were declared legally dead, but their disappearance remains a mystery.