In 2003, a Minnesota resident named Lyle Christiansen watched a television documentary about the Cooper hijacking and became convinced that his late brother Kenneth (1926–1994) was Cooper. After repeated futile attempts to convince first the FBI, and then the author and film director Nora Ephron (whom he hoped would make a movie about the case), he contacted a private investigator in New York City. In 2010 the detective, Skipp Porteous, published a book postulating that Christiansen was the hijacker. The following year, an episode of the History series "Brad Meltzer's Decoded" also summarized the circumstantial evidence linking Christiansen to the Cooper case.