'I Can't Believe I'm Still Alive:' Survivor Who Fought Back Against Child Killer Shares Her Story

A woman who bravely fought off a ruthless serial killer, known for preying on kids, is now speaking out about the ordeal.

Survivor Fabienne Witherspoon will share her story for the very first time in a two-hour “20/20” special which runs on Friday. 

Witherspoon was just a teenager when she was attacked by Tommy Lynn Sells, a man suspected of killing 22 people. He was executed in 1999 for the murder of a 13-year-old girl, the only murder he had been convicted of, though claimed to have killed dozens more.

There are only two known survivors of his attacks, and one is Witherspoon. She was attacked while trying to help Sells, whom she met as she was walking to a friend’s home in West Virginia in 1992. She'd noticed he was holding a sign asking for food, a press release from “20/20” states. She was further manipulated by him after he showed her a picture of his family.

She offered to assist him and let him follow her to her friend’s home. She asked him to wait outside as she picked up some clothes and food for him from inside her pal’s apartment.

But Sells had different intentions.

“And I guess while I was doing that, he had come in the house and gotten a knife,” Witherspoon says in the upcoming episode.

Sells then led the teenager to the bathroom.

“I just thought, ‘Okay, I'll get through this. I'll get through this, and then he'll leave, and then everything will be okay.’ But then it came to a point that I was panicking and looking out through the shower,” Witherspoon says.

When Sells told her he was going to rape her, Witherspoon physically attacked him.

“He had pushed me up against where the toilet was, and I saw on the back of the toilet was a ceramic duck,” Witherspoon recalls “So I grabbed the duck and I'm thinking in my head, ‘In the movies, if you get hit over the head with something, they pass out. They lose consciousness.’ So I picked the duck up, and I started repeatedly hitting him over the head with the duck … and he was still standing.”

The incident was so intense she didn’t even realize that she had used the knife on him.

“I just wanted to get away, and I didn't realize I had stabbed him,” Witherspoon tells “20/20.” “And it was very, very, very hard to know that I had the capability of hurting someone like that.”

At this point, nobody knew that Sells was a serial killer. Following the attack, Sells was arrested and took a plea deal on malicious wounding charges and served five years in prison.

“I felt like it was my fault that he only got five years,” Witherspoon says in the upcoming episode. “I've read … that after he had his encounter with me, he never wanted to be stuck in that situation again where he could be at jeopardy of being hurt, so he turned to smaller people or children after that.”

Many of Sells’ suspected victims were children, the youngest of whom was only 4 years old.