narrator: srihari's conclusion does not completely eliminate knoll as a suspect. but it means john douglas must dig deeper into knoll's story to prove he's a lost kidnapper. john, my dad grew up in this south bronx neighborhood. it was a german neighborhood at the time. narrator: douglas's key question: does zorn have evidence knoll and hauptmann ever met? zorn: my grandparents rented a third-floor flat in one of the homes and john knoll lived three doors down in the second floor of an apartment. he rented a home for ten dollars a month. well, it's very interesting. but how would knoll and hauptmann get to know each other? what makes you think there's a connection? well, when hauptmann came to the states in 1923 he immediately started coming and visiting people from his home village of kamenz. as it turned out my grandparents' landlord was from that same home village of kamenz. narrator: if zorn is right hauptmann would have come to this german neighborhood to meet his hometown friend. and that friend would have surely introduced him to his german neighbor and dri