Story highlights Parents of slain Virginia reporter Alison Parker appear together on CNN

Andy and Barbara Parker vow to bring about change

(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.

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