THE notorious US serial killer known as the BTK has revealed he believes a "demon" inside of him drove him to murder 10 people, including two children.

In a previously unheard interview, Rader opened up about his crimes as well as his childhood, soon after he confessed 13 years ago.

7 Dennis Rader, 73, appearing in court for sentencing after his brutal crimes Credit: Reuters

Wichita, Kansas-native Rader called himself the BTK, which stood for Bind, Torture, and Kill.

He was arrested in 2005 and is serving 10 consecutive life sentences at a Kansas prison for his crimes.

A new Oxygen documentary titled Snapped: Notorious BTK Serial Killer will include Rader as its main subject, including an unheard interview he gave to a local television reporter after he confessed to the murders.

"How could a guy like me, church member, raised a family, go out and do those sort of things?" he told reporter Larry Hatteberg during the interview on KAKE-TV.

7 Dennis Rader pictured in 2005 after being sentenced to 10 consecutive life sentences Credit: AFP - Getty

"I want the people of Sedgwick County, the United States and the world to know that I am a serial killer."

Rader then told Hatteburg what urged him to commit his crimes.

He said: "I personally think, and I know it’s not very Christian, but I actually think it’s a demon that’s within me.

"At some point in time, it entered me when I was young, and it basically controlled me."

Hatteburg asked him if he had any feelings for the 10 victims which Rader had killed, Rader replied: "Yes I do.

7 Wichita Police Det. Sam Houston shows a mask during the sentencing hearing that Rader placed on one of his victims Credit: Getty - Pool

"I mean, I have a lot of feelings for them."

Rader also revealed how the murders made him feel.

He said: "I guess it’s more of an achievement for this object in the hunt, or sort of more of a high."

Rader was a former church leader and lived at home with his wife and two children.

He hid all of his killings from his family and said in the interview that he started noticing his dark side back in eighth grade (Year 9).

Notorious BTK serial killer Dennis Rader confesses to murders during 2005 trial

7 Above are 8 of the 10 victims which Dennis Rader murdered between 1974 to 1991 Credit: The Wichita Eagle

He previously said that lust and desire for fame and power drove him to murder, MailOnline reports.

For over 30 years, Rader evaded authorities but continuously taunted police about the killings, which later led to his downfall.

He also communicated with Wichita police detectives via a floppy disk, which eventually authorities traced back to his church.

In 2016 Rader worked with Katherine Ramsland, a forensic psychology professor at DeSales University, to publish a book Confessions of a Serial Killer: The Untold Story of Dennis Rader, BTK Killer about his crimes.

7 Rader said he started noticing his dark side back in eighth grade Credit: Getty - Pool

Ramsland wrote the book under an agreement that proceeds from its sale goes to the victims’ families’ trust fund.

The book contained three-and-a-half pages about his plans to kill his 11th victim, who he was planning on hanging upside down in her home before he was arrested.

"This was supposed to be my opus, my grand finale, and to make it different, I would set the house on fire using propane canisters," he wrote.

Rader got far enough to get into the woman’s garden, and knocked on her door, but aborted his plan when a city street crew showed up unexpectedly to work outside the house.

7 Rader is now the subject of a new documentary titled Snapped: Notorious BTK Serial Killer

His murder plan was moved to the following Spring but he was arrested in February 2005.

Wichita police detectives said that Rader showed pride and shared many details about the tortures he planned to inflict on the 11th victim.

Following his arrest, several of the victims’ relatives sued Rader and secured a settlement that agreed he could never profit from his crimes or coverage of them.

Rader’s murders include the brutal slaying of four members of the Otero family in 1974.

7 Rader, who called himself BTK for Bind, Torture and Kill, once dressed up as one of his victims

He killed the mother and father, as well as their two children, aged 11 and 9. Otero’s third child discovered the carnage when he came home from school later that day.

His next murder was a few months later when he killed 21-year-old Kathryn Bright by stabbing her to death in her home.

Three years later he reappeared in 1977 when he entered the home of 24-year-old Shirley Vian.

Rader locked her children in the bathroom and strangled the woman to death.

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He strangled another woman later that year which put every resident of Wichita in fear.

In 1985 he strangled 53-year-old Marine Hedge in her home on the suburbs of Wichita.

He later strangled two more women to death in 1986 and 1991.