'Mindhunter' S2 Finally Uncovers the Sinister True Story of the BTK Killer

The real-life story behind Dennis Rader, America's most prolific serial killer.

It’s the mid 1970s and American is in a state of flux — about its identity after the unrest of the ‘60s, and thanks to a general distrust in the government after the Watergate scandal. Meanwhile, there’s been an uptick in a violent string of murderers across the nation, soon to be coined “serial killers” by the FBI’s Behavioral Science Unit (BSU) as portrayed in Mindhunter Season 2, where the Netflix series finally matches a name to a familiar face on the show known as the BTK Killer.

Mindhunter Season 2 doesn’t waste any time getting right into it. FBI investigate duo Bill Tench (Holt McCallany) and Holden Ford (Jonathan Groff), and psychologist Wendy Carr (Anna Torv) have their hands full not only analyzing the working minds of America’s most prolific killers, from Charles Manson to the Son of Sam, but also identifying a man going by the name of BTK, or “Bind, Torture, Kill.”

At this point, the audience knows more than its cast as Season 2 lifts the curtain back to reveal that the mysterious man the show keeps revisiting in a series of creepy and increasingly unsettling vignettes is, in fact, the BTK Killer.

Nearly everything in Mindhunter is based on true and often chilling facts, including the enigmatic double life of the BTK Killer, so let’s dive in.

Dennis Rader mugshot
Rader's mugshot at the El Dorado Correctional Facility in Kansas.

Who Is Dennis Rader, the BTK Killer?

Dennis Rader, later known to the American public as the BTK Killer, murdered 10 people in Wichita, Kansas, for which he is currently serving out 10 consecutive life sentences at the El Dorado Correctional Facility. His killings started in 1974 and lasted nearly two decades, up until 1991. It wouldn’t be until 2005, more than 10 years later, that he was finally caught and arrested after letters signed by his alter ego started to resurface.

On Mindhunter, the FBI is soon made aware of the BTK Killer after he admits to the murder of four members of the Otero family, who were strangled in their home in January of 1974, which he details in a letter made public by the media. The letter was in fact real and ended up in the local newspaper, The Wichita Eagle, after it was found in a public library book, where we often see him “at work” on the show. The Wichita Eagle later released excerpts from the poorly typed letter to the public in 2005, which revealed his admissions of guilt:

I can’t stop it so the monster goes on, and hurt me as well as society. Society can be thankful that there are ways for people like me to relieve myself at time by day dreams of some victims being torture and being mine. It a big compicated game my friend of the monster play putting victims number down, follow them, checking up on them waiting in the dark, waiting, waiting… the pressure is great and sometimes he run the game to his liking. Maybe you can stop him. I can’t. He has aready chosen his next victim or victims. I don’t who they are yet. The next day after I read the paper, I will know, but it to late. Good luck hunting.

“YOURS, TRULY GUILTILY”

P.S. Since sex criminals do not change their M.O. or by nature cannot do so, I will not change mine. The code words for me will be… Bind them, toture them, kill them, B.T.K., you see he at it again. They will be on the next victim.

This would be the first of a series of letters written to the media taunting them much in the same way as notorious NY serial killer David Berkowitz, aka the Son of Sam, who was thought to have served as inspiration for the BTK Killer. Just like Season 2, Episode 2 depicts, real-life FBI agents John E. Douglas (Ford) and Robert Ressler (Tench) made mention of the BTK Killer with Berkowitz during his interview, expressing that they believed him to be exhibiting a similar modeled behavior to the Son of Sam. In Douglas’ book, along with coauthor Mark Olshaker, Mindhunter: Inside the FBI’s Elite Serial Crime Unit, he describes this particular encounter with Berkowitz, noting BTK’s copycat tendencies:

I hold up the New York Daily News, then pass it across the table to him as I say, “David, a hundred years from now no one is going to remember Bob Ressler or John Douglas, but they will remember the Son of Sam. In fact, right now there’s a case in Wichita, Kansas, a guy who’s killed about half a dozen women and calling himself the BTK Strangler. That’s ‘bind, torture, kill.’ And you know, he’s writing letters and he’s talking about you in those letters … He wants to be like you because you have this power. I wouldn’t even be surprised if he writes you a letter in jail here.”

Mindhunter S2
Tench (McCallany) and Ford (Groff) interview the Son of Sam.

How Is the BTK Killer Different From the Son of Sam?

While Berkowitz was thought to have had a troublesome past, Rader was brought up in a seemingly normal childhood. He married his wife, Paula Dietz, in 1971 after a stint in the US Air Force and later worked for ADT Security Services. He was known to be an attentive husband and father to two children and even served as a Boy Scout troop leader and president of his church council. But as Co-ed Killer Ed Kemper explains to Holden in Episode 5, not all serial killers have trouble managing real life; they “live like any other person, have relationships, hold down a job.”

What was so disturbing about Rader was how easily he was able to live this double life, flying under the radar for so many years. All in all, he seemed like a perfectly normal, upstanding member of society. But as the courtroom later learned the gruesome details of his alter ego, he had a deep fascination with bondage, and would photograph himself dressed like his victims, tied to a chair, and wearing a painted mask — further driving the point home, as is often illustrated on Mindhunter, that not everything is as it seems.


Mindhunter Seasons 1 and 2 are now streaming on Netflix.