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ATLANTA, Georgia (CNN) — It's been less than a week since murder set their lives onto a new course, into roles they never wanted to take on and into a battle they never planned to fight.
But only five days in, Andy and Barbara Parker — the parents of slain television journalist Alison Parker — speak about gun control with a passion as if they'd spent their lifetimes fighting for it.
"You can't change the world in a day," Barbara Parker told CNN. "But we cannot be intimidated, we cannot be pushed aside."
On Wednesday, Alison Parker and cameraman Adam Ward — two journalists for WDBJ in Roanoke, Virginia — were killed on live television by a disgruntled former employee.
In the days since, Andy Parker has emerged as perhaps the world's most visible advocate for gun control, making numerous appearances on numerous networks and even holding a news conference.
On Sunday, both of the Parkers spoke to CNN's Poppy Harlow, telling her that ending gun violence has become each of their lives' missions -- and the grieving parents pledged to be as unrelenting and as feisty as their daughter in achieving it.
"Alison would be really mad at me if I didn't take this on," said Andy Parker. "And I promise you, these people are messing with the wrong family. We are going to effect a change."
Earlier in the day, Andy Parker said on "State of the Union" with Jake Tapper that he'd been in touch with several influential gun control advocates -- including Mark Kelly, the astronaut husband of former Rep. Gabrielle Giffords -- about pushing "sensible gun control legislation."
I promise you, these people are messing with the wrong family. We are going to effect a change.
Giffords, a former Arizona congresswoman, was shot in the head during a 2011 shooting rampage in which six people were killed.
To effectuate change, however, Parker said the nation cannot become "desensitized to this issue," and let it fade from the public consciousness.
"Every time there has been one of these tragedies, we all say, 'this is the tipping point. Something is gonna get done,' he told Harlow.
"After Newtown, after Aurora, after Gabby Giffords was shot -- you think, something is gonna get done. This time, the circumstances of this tragedy, they are different."
Barbara Parker said she is not discouraged by the fact that those previous mass shootings failed to be the tipping point when it came to gun control, nor is she fazed by the often fervent -- and well-financed -- defenders of the Second Amendment.
"There are people out there whose minds we will never change," she said. "If you are a parent, if you are a mother, if you have children -- how can you look your child in the eye and say we are willing to allow you to be collateral damage in order to keep what some people perceive to be their constitutional rights? If we as a society are willing to accept that, what kind of society are we?"
Choking back tears, Andy Parker said it's his daughter that will give him the strength to carry the mission on.
"I know somewhere she'd be looking down saying, 'You go, dad.' "
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