Transcript for Woman recalls moment she found out her father was the BTK serial killer: Part 1
name ??? I'm walking on the street I grew up on, Independence street. I just remember riding my bike up and down this street and running around in my friends yards and sleepovers and playing hopscotch and playing in the rain puddles on this street. So you were safe. My parents would let me ride my bike all over. This road really just reminds me of childhood. On February 25th, 2005 when I found out my father was arrested this place became not my home. And no one ever slept in my house again. You okay? Yeah. Are we good? Everybody is rolling? Reporter: It's been more than a decade since your life, as you knew it -- Uh-huh. Reporter: -- Changed forever. What do you remember about that day? It was a Normal day. I had slept in. I was substitute teaching and I would -- just took the day off. And then there's a knock on my door. So I'm already thinking who is this person in my apartment building. He said he was the FBI. Reporter: Is there any reason you should even expect the FBI to be -- No. Reporter: -- At your home? No. Reporter: What does he say, exactly? He asked, "Do you know who btk is?" I was like, "You mean the person that's wanted for murders back in Kansas?" And then he says, "Your dad has been arrested as btk." I was like, saying, "I think I'm going to pass out." . Reporter: He calls himself btk strangler and promises to kill again. Reporter: Btk's brutal crimes shocked Wichita. Reporter: The most infamous, unsolved serial killing spree in Wichita history. Btk stood for bind, torture, kill, and that was his M.O. Reporter: Three letters that can touch off memories for anyone who lived in Wichita in the 1970s. Btk emerged in 1974. When btk came forward, everybody's life changed. It was really part of Wichita's history. Reporter: The btk killings changed the way people lived in Wichita. It changed Wichita from a sleepy little, friendly town into a place and a city where you now lock your door and you check your phone and make sure you have a dial tone. We're asking that anyone with information on this case please call our crime stoppers line. Reporter: The body was discovered here. I think we'll solve the crime. The question is when will we solve the crime? Btk was a monster, who killed a total of 10 people, two of those children, in cold blood. This was a serial killer who got away with it for 30 years. That's very rare. There was somebody out there targeting women and children. Btk was the boogeyman made real. He would be driving down the street, and he would see a woman walking, or a woman on the front porch, and he would look at her, and he would say she's next. The killings were random. He would break into someone's home, hide in a closet, wait hours until they were fast asleep and then attack. To this day I still check inside the closets, under the bed, behind the shower curtain when I'm in unfamiliar territory. You never knew when he was going to show up, and you never knew where he was going to be next. People were really frightened. This is one of the most challenging cases that I've ever been involved with. None of the women were actually physically sexually assaulted. What he wanted was the image of a bound woman. He killed in the '70s proficiently, and then stopped it seemed. It became almost mythology. This figure came. He killed a bunch of people and then he left. It was kinda slipping into history when in 2004 a mailing come and there was no question who it was from. Police in Wichita Kansas are investigating the possible return of a serial killer. A serial killer who calls himself btk resurfaces after 25 years. This is kak E! News. We have exclusive details on a new communication that could be from the serial killer. We were all scared to death to see if he was going to kill again and was I going to be the next victim? It scares me to be out by myself anymore. For the second time in just over a week another possible communication from btk arrives here at our studios. He thrived on the publicity and I think he thrived on scaring the heck out of everybody in this city. We begin tonight with breaking news in the case. Btk is arrested. His hunger for publicity seems to have done him in. We have learned that Rader has been charged now with ten counts of first degree murder. He was living a double life here in Wichita. Residents are still trying to digest that a possible serial killer lived among them. Nobody would've imagined this church leader, this father, this good husband as somebody that could even contemplate the murders that he committed. Btk was literally the guy next door with a wife and two kids. Everybody wanted to talk to the family members, everybody did. How do you process this earth-shattering news? You don't. I said, "Can I call my husband? He needs to come home." All this stuff is running through my head, or I'm like did somebody get hurt? But why would it be the FBI? So when I get home, I remember him saying, "He said, 'have you heard about the btk, the serial killer? We're pretty sure he's the guy. We got the guy." I was trying to almost alibi my father. I was like, "My father's a good guy. He's, like, boy scout leader. You know, president of the church." I'm like, "You've got the wrong man." You don't believe it's true and you don't want it to be true. And you know your father's not -- the father you know is not capable of any of this. Reporter: Were you worried at that point that your mom was somehow involved in this as well? No, I never imagined that my mom was involved in anything bad. I was very -- worried about her and wanted to call her and let her know I was okay. And I wanted to know how my brother was doing. He was stationed in Connecticut with the Navy. And so, like, I wasn't able to talk to my mom or my brother like six or seven hours after the arrest. When you first heard her voice on the phone -- Just heartbreaking. Like, you could just hear her break. How is Mrs. Rader doing? She's having a very difficult time with all this. In shock. Just unbelievable. Totally in disbelief. Police are being very tight lipped about the evidence against him but there are reports the suspect is confessing to many of the murders. When did you type this? Well, it probably would help to have a calendar. So you're trying to deny this. And your father is confessing to being a serial killer. Right. I was like what is he confessing to? You're not with it. You're like what is he confessing to. They're like he's confessing to the crimes. Reporter: After your dad's arrest, you began to really dig into this and began to look. You actually started googling, trying to see what you can find out about this killer and also about your dad.
This transcript has been automatically generated and may not be 100% accurate.