In a crowded gym just outside Kansas City, Mo., 300 women and girls are learning to fight back.
They are there because of a girl most of them never met - Ali Kemp.
"We wanted to do this self-defense class in honor of Ali," said Roger Kemp, Ali Kemp's father and the founder of the Kemp TAKE Foundation, "because Ali fought and fought for her life."
But tragically 19-year-old Ali didn't make it. In 2002, the only daughter of Roger and Kathy Kemp was brutally raped and strangled at her neighborhood pool. Her parents faced the unimaginable: How to go on in a world without Ali.
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"Early on I realized you have two choices: You can pull the covers over your head and stay in bed, or you can get out and say you're going to fight it," Roger Kemp said. "And I fought it."
His first mission was to find Ali's killer. Two years passed and then Kemp had a revelation.
"I was driving by and saw a billboard near where Ali is buried and thought, 'Why not?'" he said.
He put up what looked like an old-fashioned wanted poster. Outdoor advertising company Lamar donated some of the billboards and a national trade group pushed them nationwide.
And. The billboard generated tips that led police to the predator. Law enforcement took notice and Kemp's idea took off. Similar billboards are now up in 40 states.
But catching his daughter's killer wasn't enough for Kemp. He wanted to make sure other girls got the fighting chance his daughter did not.
He set up a foundation in Ali's name and began offering free self-defense training. Since 2005, more than 38,000 women in 15 states have learned basic skills.
Carolyn Regimand came to a recent training event with her two daughters Akarra and Sarra.
"I hope it never happens to me, but if it does, I'll know what to do," Sarra said.
Giving girls that sense of empowerment is what gives Roger Kemp a sense of purpose.
Kemp says he hopes his daughter would be proud of him.
"I'm sure proud of her," he said. "Her mother and I always thought she was going to make a difference in this world."
And she is making a difference to thousands of women around the country.