She insists Steven Powell robbed her daughters of a normal life and is forcing them to live with a secret -- and they are determined to keep pressure on him.
"It was so shocking, unnerving and scary for us as a family," said the mother, who wishes to remain anonymous.
She says Steven Powell violated her children and forever connected her family to a case that has captured the nation's attention: the disappearance of Susan Powell, and her husband Josh, the prime suspect who killed himself and his children in a fire.
"It's been rough, because it's not something we want to talk about to people that we know who might not know this happened to us, because I want them to have normal lives," she said.
Her daughters' friends and classmates have no idea Steven Powell's voyeurism conviction hinged on images he captured of the sisters unclothed in the bathroom. They were were just 8 and 10 at the time. As next door neighbors, Powell shot out his window into their window.
"He took the video and took the pieces that he liked and he put them in a loop and he... I'm sorry," she said, trailing off, unable to finish the sentence.
For the first time we realize how desperate Powell was to capture those shots: It took a powerful lens and patience as he shot through a hallway window, across the length of the house and into an open door to the bathroom.
"I didn't know that was even possible with the way our house was arranged," she said. "I was shocked. I couldn't believe it."
The images were uncovered during an investigation into the the disappearance of Susan Powell, as some of the discovered photos were of her.
"I think my girls are sad that she didn't get her justice," the mom said.
The family is now filing a lawsuit accusing Powell of violating the girls' privacy, while the girls hope it will pressure Powell to discuss Susan's disappearance.
"They are praying for them and hoping that everything turns out to where they can find where Susan is," she said.
She's hoping for something else too.
"I was upset with him because he never owned up to what he did -- he never apologized, not once," she said.
Anne Bremner, the victim's attorney, says she will file that lawsuit against Steven Powell this week.
The family isn't expecting any substantial pay day, but they do hope it may lead to what no one has been able to do for more than two-and-a-half years, find Susan Powell.