“My mother's ex-husband Steve was a sick, abusive narcissist,” says Jessica.

“Steve would use tickling as a game, as an excuse to touch us,” adds her sister Amber.

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The women claim that shortly after their mom married Steve, he began to sexually abuse them.

“It would happen at night when we were watching TV and nobody else was around,” claims Jessica, who says Steve molested her from the ages of 9-16. “Steve would start at my feet, rubbing it, and he would start working his way up my leg towards my private part. He would pretend to be sleeping, but I knew he was awake because I could feel his hand start to shake.”

WATCH: Woman Who Claims She Was Abused By Stepdad: ‘Steve Would Say ‘Let’s Tingle Each Other’’

Amber says the last time Steve touched her, he pushed himself up against her, started to kiss her and grab her chest. “You could tell that he was excited,” she claims. “I remember, like, kicking him and running out of the house.”

The girls say they told their mom about the molestation, and Steve was later arrested. Although he has always denied any sexual abuse toward the girls, he took a plea deal in which he did not have to admit guilt.

WATCH: Man Claims Stepdaughters Lied ‘To Put Me In Jail’

“After all these years, I still haven’t gotten over what Steve’s done to me,” Jessica says.

“I want him to take responsibility for what he did,” Amber adds.

On Monday's episode of Dr. Phil, hear from Steve who adamantly denies the accusations. And, see what happens when the sisters confront Steve for the first time in 10 years. Plus, Steve agrees to take a polygraph exam. On Tuesday, see what his results reveal. Check here to see where you can watch.

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