Carla Lenz, 17, disappeared on Nov. 12, 1986. Her brother-in-law, John R. Weber, nearly killed her sister two years later. During the search of the Weber property, police found a cassette tape in which Weber spoke in great detail about Carla’s horrific death. — Trigger Warning: This article contains graphic details of sexual assault and violence that some readers may find distressing. Gene and Caroline Lenz married on April 21, 1966, in Beresford, South Dakota, and ultimately had five children together — three sons and two daughters, Emily and Carla. Gene Lenz has two…