In 1976, Herman Knippenberg, a 31-year-old Dutch diplomat, received a letter from the relative of two missing backpackers. © Getty Images The twisted true story behind Netflix's addictive new crime series, The Serpent. The two backpackers, Henk Bintanja, 29, and his fiancée Cornelia Hemker, 25, had stopped communicating with their families. Load Error Shortly afterwards, ...
