IN THE SHADOW OF MT. DIABLO

An amateur sleuth presents his case that a San Francisco businessman was the Zodiac Killer in this nonfiction book.

Uncovering the identity of the Zodiac Killer who terrorized the San Francisco Bay Area in the late 1960s, slaying five people, has become the holy grail for a legion of amateur investigators hoping to achieve what several police agencies failed to do. One of the most industrious has been Rodelli, who for the last 20 years has pursued the theory that the killer was Kjell Qvale, a wealthy San Francisco entrepreneur. Since June 1999, when the author saw a letter Qvale wrote to the San Francisco Chronicle that galvanized his research, he has been “consumed with a passion” for the case to the point of “literally not being able to wait to get out of bed in the morning to see what new discoveries awaited me,” he writes in this voluminous account of his endeavors that is a worthy, if not definitive, addition to the body of Zodiac knowledge. Like Michelle McNamara, who described her meticulous pursuit of the Golden State Killer in I’ll Be Gone in the Dark (2018), Rodelli leaves no stone unturned, even contacting an archive in Norway for information on Qvale’s genealogy. In 2006, the author landed an interview with his suspect, who told him he was “seeing what” he wanted “to see.” (Qvale died in 2013.) Rodelli’s suspicions are based largely on the work of a behavioral profiler, who concluded that the Zodiac’s crimes “were consistent with what is known as an ‘organized, nonsexual, power-assertive (P-A) killer with sociopathic traits,’ ” and “a very large iceberg of circumstantial evidence.” The “life story of Kjell Qvale,” the author insists, “also tells the story of the Zodiac.” But some of the book’s inferences strain credulity—for example, that the Zodiac used geometry as part of his crimes—and the “power-assertive” profiling seems as speculative as many of the other theories surrounding the case. The Zodiac stopped killing, Rodelli theorizes, because his “entrepreneurial business empire” gave him “an alternative source of power and control in his life.” But Qvale already was a successful entrepreneur before the murders, and it is a stretch to suggest that a business empire could somehow be a substitute for the power of taking a human life.

A thorough, rigorous Zodiac account, but the use of behavioral profiling may be speculative.