Transcript for How Kerri Rawson learned her dad was 'BTK' serial killer

It's been more than a decade since your life. As you knew it changed forever. What do you remember about that day it was a normal day I slept and I was substitute teaching and I just today off. And then there's a knock on my door I'm already like appetite that he might choose a person. You know and in my apartment helping. And then he said he was the FBI is a key reason you should even expect the FBI know all know what does he saves them. He asked do you know who BTK as I was like you mean a person has wanted for murder is back in Kansas. And then eases your dad has been arrested as BTK. Police gleaned through your mind mainly just. Shock he was asking me questions about my dad about eight some things and I was trying thinks I was trying to alibi my honor Wesley. My father is a good guy lose my. Boy scout leader present and in the church. You got the wrong man all. Wow.

This transcript has been automatically generated and may not be 100% accurate.