Kerri Rawson, the daughter of BTK Killer Dennis Rader, did not know her DNA was being used by investigators
But she also unwittingly gave police the final piece of the puzzle they’d spent 30 years searching for — and unmasked her father as the brutal “BTK” serial killer who had terrorized her hometown of Wichita, Kans., for decades.
Rader killed ten people between 1974 and 1991 while taunting police to catch him — and giving himself the nickname BTK, which stands for “bind, torture and kill” — before the killings stopped.
He was finally arrested in 2005 after resurfacing to announce that he was preparing to kill again.
But detectives traced a computer disc he sent them — with Rader’s name embedded in the disc’s metadata — to a local Lutheran church where he volunteered.
Before they could arrest Rader, however, police needed to match DNA evidence to the scenes of the murders.
And that’s where Rawson — whose new memoir, A Serial Killer’s Daughter (released on Jan. 29), chronicles how her horror and anger were tempered by the love she felt for her father — came in.
“They found out I had had annual pap smears and they got a warrant for my medical records,” Rawson says in an ABC 20/20 documentary on that airs tonight at 9 p.m. ET. “It would have been nice if somebody had asked me for my DNA. I would have willingly given it.”
It has taken Rawson nearly 14 years to be able to finally talk about her father’s secret double life and his arrest — which devastated her family and nearly destroyed her.
“I understand why nobody approached me,” she says in the documentary. “They needed to catch my dad. They needed to be safe about it and needed to do it quickly.”
Rawson, now a 40-year-old married mother of two, was initially angry when she learned that police had taken her medical records. “It felt,” she says, “like an invasion of my privacy.”
But she eventually understood that they had no choice.
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“They were just doing their job and they were heroes,” she told PEOPLE in last week’s cover story. “They were trying to save the community [in Wichita] and prevent him from committing any more murders.”
After pleading guilty to ten murders, Rader is now serving a 175-year sentence.
“I’m not forgiving him for what he did to those other families,” says Rawson. “But I am forgiving him for what he did to our family.”
The two-hour 20/20 documentary airs tonight at 9pm ET on ABC.