Niquelle says that she always noticed her friend Kelly had a “weird” relationship with her father. She says Kelly and her father were always texting each other and were very affectionate toward one another.

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“They acted like a married couple, almost to the point where people would question it,” Niquelle says. “If we ever wanted to go out, like, shopping or just take the kids out, he always had to come with us.”

WATCH: Woman Claims Father Made Her His Wife, Sex Slave And Fathered Her Two Children

Niquelle says she asked Kelly if she was sleeping with her father, and Kelly told her “there was no way that was happening” -- but then changed her story.

“Kelly called me crying and told me that she had been sleeping with her father, and that both children were his,” Niquelle says.

WATCH: Why Woman Says She 'Threw Up' Her Hands And Stopped Fighting To Get Custody Of Her Children

She says after Kelly wouldn’t call the police, she did.

“I figured it was better to lose a friend and save lives,” Niquelle says.

Watch the video above to find out what happened after Niquelle called the police and how it changed Kelly’s life forever. And on Tuesday’s episode of Dr. Phil, hear Kelly’s harrowing story. Check here to see where you can watch.

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‘I Gave Birth To Two Children Who Were Fathered By My Dad’