Kerri Rawson says her life was changed one day in 2005 forever.

TELL DR. PHIL YOUR STORY: Are you involved in a story that has made the headlines?

“The FBI knocked on my door to tell me that my father had been arrested, and they said they thought he was BTK,” Kerri recalls, referring to the notorious serial killer. “I was worried something had happened to my mom or my grandma because BTK strangled women that lived alone, and they’re, like, ‘No. We’re trying to tell you that your father is BTK.’”

Rawson says she told them they had the wrong guy because her father, Dennis Rader, was a church volunteer and Boy Scout leader. Rawson soon learned that the man she loved and was extremely close with had terrorized Wichita, Kansas for 17 years, murdering eight adults and two children, all while coming home to her family and being a hands-on father and husband.

WATCH: What The Notorious BTK Strangler Said About Murdering His First Victims

On Wednesday’s episode of Dr. Phil, Rawson, author of A Serial Killer’s Daughter: My Story of Faith, Love, And Overcoming, shares her story. Did she ever see any red flags in her father’s behavior? Watch more of her story in the video above.

And on Wednesday, Rawson shares some of the letters her father, who is serving 10 life sentences, has written to her. Check here to see where you can watch.

Woman Reveals What It Was Like Growing Up With A Serial Killer Father