<p><b>The desire to kill is becoming contagious in this riveting novel of conceivable mad science by the <i>Wall Street Journal</i> bestselling author of <i>The Naturalist</i>.</b></p><p>Computational biologist and serial-killer hunter Dr. Theo Cray receives an off-the-record request from the FBI to investigate an inexplicable double homicide. It happened at the excavation site where a murderer had buried his victims’ remains. In custody is a forensic technician in shock, with no history of aggression. He doesn’t remember a thing. His colleagues don’t even recognize the man they thought they knew. But an MRI reveals something peculiar. And abnormal.</p><p>What on earth made him commit murder?</p><p>After discovering that a mysterious man has been stalking crime scenes and stealing forensic data, Cray has a radical and terrifying theory. Now he must race against time to find a darker version of himself: a scientist with an obsession in pathological behavior who uses his genius not to catch serial killers—but to create them.</p>