Doerkson further argues that Morrison's theories of a genetic cause for the impulse to serial murder are insufficiently rigorous and not supported by existing scientific evidence. He additionally follows Bell in questioning Morrison's claim to have interviewed over 80 serial killers, when even an extremely significant expert in the field of serial homicide such as Robert Ressler has only interviewed roughly 40. The piece also includes interviews with several law enforcement professionals who were featured in Morrison's book, each of whom claim that Morrison has misrepresented some of the events in the book.