It was a reference to a speech Clinton, then first lady, gave in 1996, of a crime bill passed two years earlier. At the time, Clinton said, according to The Washington Post:
"They are not just gangs of kids anymore. They are often the kinds of kids that are called 'superpredators.' No conscience, no empathy. We can talk about why they ended up that way, but first we have to bring them to heel."
Clinton, on Thursday, said she wanted to explain, but the protester had been removed from the room. Later, Clinton told the Post:
"In that speech, I was talking about the impact violent crime and vicious drug cartels were having on communities across the country and the particular danger they posed to children and families. Looking back, I shouldn't have used those words, and I wouldn't use them today."
Moving from Georgia State's Student Center to City Hall allows Clinton to better control the audience. Which would also help prevent instances like the protest which happened on a visit to Atlanta in October, when Black Lives Matter demonstrators interrupted a speech she gave at Clark Atlanta University.
A person with knowledge of the move said it was switched to accommodate the schedule of Atlanta Mayor Kasim Reed, a Clinton supporter.
The person said schedules are fluid and that venue changes are par for the course. But the last-minute switch raises questions that the campaign wanted to more strictly control her events on the eve of the South Carolina primary, a must-win for Clinton's White House bid.
Reed's office did not immediately response to a request for comment. The campaign said Clinton was looking forward to the event with Reed.
"Hillary Clinton is excited to return to Atlanta to campaign and grateful to be with her longtime friend and supporter Mayor Reed," said Clinton spokeswoman Priyanka Mantha.