Why Was Dennis Rader, The BTK Serial Killer, Obsessed With Knots And Bondage?

While speaking with investigators, Dennis Rader opened up about defining moments in his childhood that hinted at his future as the BTK serial killer.

Exclusive
Square Knots Link BTK Killings
oxygen Insider Exclusive!

Create a free profile to get unlimited access to exclusive videos, sweepstakes, and more!

Sign Up for Free to View

Square Knots Link BTK Killings

The murders of the four members of the Otero family were nearly four months apart from the murder of Kathryn Bright. Investigators discovered a unique set of square knots that were used to bind the victims of both crime scenes, helping them link both scenes to the same killer — BTK.

Between 1974 and 1991, Dennis Rader murdered 10 people around Wichita, Kansas under the moniker BTK Killer, standing for "Bind, Torture, Kill.”  

Although Rader’s modus operandi and victim selection didn’t fit a distinct pattern, one piece of evidence appeared to connect the crime scenes — intricate knots used to bind and control the victims. 

“Those square knots just screamed out to the investigators, ‘I know I’m just a little knot, but look at me. I’ve got something important to tell you about this killer.’ This is the signature mark of BTK,” Ray Lundin from the Kansas Bureau of Investigation told “Mark of a Killer,” airing Saturdays at 7/6c on Oxygen

Rader was taken into custody in 2005 after a familial DNA sample tied him to BTK crime scene evidence, and during his interrogation, Rader declined an attorney and instead launched into a lengthy confession. The serial killer also opened up about his fascination with bindings and square knots. 

His obsession started in childhood while playing cowboys and Indians, Rader said. When other boys tied him up, he found “the experience of being utterly helpless erotic,” explained forensic psychologist Dr. Katherine Ramsland on “Mark of a Killer.” 

Ropes Moak 209 1

Another formative moment occurred when he was 8 years old and witnessed his grandmother prepare a chicken for their Sunday dinner. She went down to the chicken coup, tied the bird’s legs together with a leather shoestring, and chopped its head off with an axe, resulting in blood squirting everywhere. 

“He said, ‘My brothers and my cousins would all run away screaming, and when I watched that, it’d give me an erection,’” said Larry Thomas from the Kansas Bureau of Investigation. 

That was the moment he knew he was different from others, Rader recalled. 

To act out these disturbing urges, Rader, a respected church leader and married father of two, developed “a secret life” in which he practiced and mastered tying the knots, bringing “to his image as a killer a sense of intelligence, superiority, and control,” said Dr. Ramsland. 

During the interrogation, Rader told investigators where they could find evidence from his 17-year killing spree, and after searching his home and office, authorities uncovered a treasure trove of newspaper clippings, mementos, trophies, and photographs.  

Some Polaroids were of Rader’s victims, while others were of himself in various forms of bondage wearing clothing and artifacts of the deceased. 

“He was practicing bondage in his photographs with the same knots and the marks that we were finding at our crime scenes,” Thomas told “Mark of a Killer.” 

By recreating images from his murders, Rader would be able to "live in that moment for years," Capt. Sam Houston of the Sedgwick County Sheriff's Office testified in 2005. 

Rader also admitted that when setting up his tripod and camera to take photographs of himself, he would often experiment with "auto-erotic activity," which involved Rader limiting his own oxygen supply to experience "a heightened feeling of euphoria during sexual release," reported CNN

Dennis Rader Moak 209

Following his confession, Rader pleaded guilty to 10 counts of first-degree murder, and he was later sentenced to 10 consecutive life terms. He is currently incarcerated at the maximum-security El Dorado Correctional Facility near Wichita, where he is being held in solitary confinement. 

Kerri Rawson, Rader’s daughter whose DNA helped lead to his arrest, told ABC’s “20/20” in 2019 that her family, including her mother and older brother, never had any clue that Rader was a serial killer. 

“Mom and I both said if we had an inkling that my father had harmed anyone, let alone murdered anyone, let alone 10, we would have gone screaming out the door to the police station,” she said. 

While Rawson initially cut off contact with her father, she has since forgiven him after a “long journey” of returning to her faith.  

“It was just a massive release,” she said on “20/20.” “I realized I was rotting within, like I didn’t just forgive my father for him, I had to do it for myself. I hope to see him in heaven someday because he could be forgiven for his sins too.” 

To hear more about Rader’s crime spree and his disturbing calling card, watch “Mark of Killer” now on Oxygen.  

Related Stories
Related Show

Crime Time is your destination for true crime stories from around the world, breaking crime news, and information about Oxygen's original true crime shows and documentaries. Sign up for our Crime Time Newsletter and subscribe to our true crime podcast Martinis & Murder for all the best true crime content. 

You May Also Like...
Recommended by Zergnet