POWAY (CBS 8) - The parents of a murdered Poway teen are marking five years since her death with renewed efforts to keep parolees from re-offending.

Chelsea's Law now requires sex offenders to take periodic polygraph tests. The Kings are calling the measure a major success.

Chelsea family visited Mount Carmel High School Thursday to highlight their work, which protects the children from violent sexual predators. Her father Brent King also spoke to students at Poway High School, where she was a beloved student.

"It's a paradox to be here. It's painfully beautiful. I feel her everywhere at Poway High School. I miss her so much. I also feel her so much," he said.

The Kings are in town making presentations at eight high school and middles schools Thursday and Friday, turning pain into purpose after Chelsea's 2010 death at the hands of convicted sex offender John Gardner. The 17-year-old – a scholar and standout athlete – was raped and killed while jogging in the hills above Lake Hodges.

Gardner also killed 14-year-old Escondido High School student Amber Dubois. He was sentenced to two consecutive life prison terms without parole.

King's parents Brent and Kelly championed California's Chelsea's Law, which mandates life prison terms for convicts of violent sex crimes against children, and stronger law enforcement oversight of sex offenders. For the first time, the state will make all paroled sex offenders take scheduled polygraph tests as a way to reduce or stop repeat offenses.

The King family is also promoting a scholarship program in Chelsea's name, and the annual Finish Chelsea's Run 5K event.

"Chelsea made a big impact on the San Diego community. It's a powerful thing to look back and say why did this kid mean so much? She lived life in a way that was spectacular," Brent King said.