The Real-Life Serial Killer Who Inspired The Trinity Killer From Dexter

The Showtime crime series "Dexter" has featured a number of terrifying serial killers over the years. Inspired by the novel "Darkly Dreaming Dexter" by Jeff Lindsay, it stars Michael C. Hall as Dexter Morgan, a blood-spatter analyst by day who stalks and murders other serial killers by night. He adheres to a strict code of conduct instilled into him by his adoptive father Harry Morgan (James Remar), a cop who took Dexter in and tried to instill in him an outlet for his need to kill. Initially, the killers and situations in "Dexter" were drawn from Lindsay's novel, but the 4th season saw the debut of a character unique to the television series: Arthur Mitchell (John Lithgow), aka the Trinity Killer.

Mitchell made his debut in the "Dexter" Season 4 premiere episode "Living The Dream" as the Trinity Killer, a mysterious figure who killed in threes and had successfully eluded the police for years. Dexter manages to successfully track him down, only to discover that Mitchell is a family man and an upstanding member of the community. Like Dexter, Mitchell presents himself as a sane and normal individual. Dexter initially believes that Mitchell could teach him how to better hide his own secret, but the man proves to be a complete monster, one whose inspiration came from real life.

Arthur Mitchell's Trinity killings all follow a ritual pattern, recreating the tragic events of his own childhood over and over again in a series of grisly killings: the abduction and murder of a 10-year-old boy, the murder of a woman by forcing her to leap off a building, and bludgeoning a man to death as part of a yearly ritual. In spite of this, Mitchell maintains a respectable home life, appearing to be a loving father and husband and active member of his church and as part of a group called Four Walls One Heart that helps construct homes for the homeless in a manner similar to Habitat for Humanity.

The concept of the Trinity Killer was inspired by real-life serial killer Dennis Rader. Rader, also known as the BTK (Bind, Torture, Kill) Killer, lived a quiet life with his wife and children for years and was a dedicated member of the Christ Lutheran Church, all the while taunting the police with letters detailing his crimes (via NBC News). Eventually, Rader was caught when he sent a file with a Christ Lutheran Church document included. On "Dexter," a similar slip-up on Mitchell's part allows the Miami police to determine a link between Mitchell's Four Walls One Heart housing units and the Trinity Killer.

In the end, Arthur Mitchell's reign of terror comes to an end at the hands of Dexter, who kills him with a hammer, Mitchell's weapon of choice in the "Dexter" Season 4 finale "Getaway". Mitchell faces Dexter's version of justice and it provides the audience with a chance for much-needed catharsis, the feeling that while Mitchell committed horrific crimes, he at least paid for them. In real life, the BTK Killer got away with his crimes for years. Between 1974 and 1981, Dennis Rader killed 10 people and was only arrested in 2005 after he himself made a mistake that alerted the authorities, per NBC News.

Shows like "Dexter" make for thrilling entertainment, and the monsters they depict are oftentimes exaggerated to heighten the drama. With Arthur Mitchell, the "Dexter" creative team took an existing monster for inspiration, which made the fictional one all the more frightening.