“It Takes a Killer” delves into some of history’s most infamous murders, exploring these crimes through the eyes of the perpetrators to understand their motivations. Esteemed homicide detectives and specialists from organizations like the FBI and Scotland Yard examine crime scene evidence and analyze the behavior of the murderers to reconstruct the specifics of each case, clarifying the timing, reasons, and methods behind each crime. For aspiring sleuths tuning in, the show also uncovers how these cases were cracked, often necessitating that investigators adopt the mindset of the criminals themselves.