An activist challenged Hillary Clinton's record on race Feb. 24, during a private fundraising event in Charleston, S.C. (YouTube/#NotASuperpredator)

COLUMBIA, S.C. — Black voters are the linchpin of Hillary Clinton's strategy for winning the South Carolina Democratic presidential primary, and as a result, her campaign has put racial justice issues at the forefront of her agenda. But at an event on Wednesday night, Clinton was vocally confronted by an activist questioning her past support for policies that had a disproportionately negative effect on African Americans.

Ashley Williams, a 23-year-old activist from Charlotte, interrupted Clinton during a private fundraiser in Charleston on Wednesday night. Williams stood and demanded an apology from Clinton for the high incarceration rate for black Americans, and confronted her with the words of a speech Clinton delivered 20 years ago voicing support for the now-debunked theory of "super-predators."

"They are often the kinds of kids that are called 'super-predators,' " Clinton said in 1996, at the height of anxiety during her husband's administration about high rates of crime and violence. "No conscience, no empathy, we can talk about why they ended up that way, but first we have to bring them to heel."

The last part of the quote was written on a large, hand-lettered sign that Williams held up as Clinton spoke to her donors and supporters.

Clinton took note of the sign and read it aloud, squinting to read it and apparently unaware that it was her own quote.

Williams addressed Clinton, asking whether Clinton would "apologize to black people for mass incarceration."

Williams added, "I'm not a super predator, Hillary Clinton."

Clinton first told Williams, "we'll talk about it," but grew irritated as Williams continued to speak.

“Do you want to hear the facts, or do you just want to talk?” Clinton asked sharply.

Off camera, guests at the fundraiser, apparently held in a private home, can be heard saying "shhhhh," which then turns to such comments as "this is inappropriate," and "you're being rude."

Williams asked again about Clinton's words from 1996, as a man approached Williams to escort her out.

"You know what? Nobody’s ever asked me before. You’re the first person to do that, and I’m happy to address it," Clinton said, but did not elaborate.

In a written response to The Washington Post's on the issue Thursday, Clinton said: “Looking back, I shouldn’t have used those words, and I wouldn’t use them today."

"My life’s work has been about lifting up children and young people who’ve been let down by the system or by society, kids who never got the chance they deserved," Clinton continued in the statement. "And unfortunately today, there are way too many of those kids, especially in African-American communities.  We haven’t done right by them.  We need to.  We need to end the school to prison pipeline and replace it with a cradle-to-college pipeline."

In an interview  Thursday, Williams said that she wanted Clinton to address her past role in supporting the country's current system of mass incarceration. Williams also said she sought an apology from Clinton for the "damage that she’s done to black communities."

"I thought that quote was important not only because it was her own words, but because that was her pathologizing black youth as these criminal, animal people," Williams told The Washington Post. "And we know that’s not right and we know that’s really racist."

"I wanted her to be confronted with that very racist thing she said," Williams said.

"As a black queer person, I understand how I don’t always get to be in control of how I’m perceived in spaces," Williams said. "I’m especially not always in control of the way I'm perceived when I'm raising my voice to speak out against injustices. So I’m not surprised that I was told that I was being rude."

In recent weeks, Clinton's 1996 comments have re-emerged as a problem, just as she has sought to push a new agenda focused on unwinding 90s-era policies that are now viewed as having had a disproportionately negative effect on African-Americans.

In a recent essay, author and law professor Michelle Alexander described Clinton's endorsement of the "super-predator" concept as "racially coded rhetoric" that was used to "cast black children as animals."

Yet, the idea wasn't Clinton's, but rather it had been invented by researchers studying crime in the 1990s. And it was used to explain the rise in violence perpetrated by youths -- particularly in predominantly minority inner cities. The concept has since been largely abandoned and decried for its racial undertones.

Twenty years later at the Charleston event, Clinton said that it was the first time that she had been asked about the comments. But Williams said she expected more.

"She’s had 20 years to respond to my question," Williams said. "And so her inability to do it last night to me is just kind of representative of how she has been absent in terms of racial justice in a meaningful way, in a material way."

The evening fundraising event was not disclosed by the Clinton campaign, although the campaign has voluntarily released information about other fundraisers in the past. The event also was not advertised to news outlets covering Clinton as she campaigns ahead of the primary vote Saturday.

Williams said she is an "independent organizer for the movement for black lives" and not part of Black Lives Matter organizations. Williams added that someone paid $500 to allow the activists to gain access to the fundraising event. Williams would not specify who contributed the money to the protest action.

Clinton has called for an end to "the era of mass incarceration" and disavowed much of the 1994 crime law signed by her husband, former president Bill Clinton. It was the disproportionate effect of that law on black people that was the protesters' main complaint.

The Clinton campaign has also pointed to her presidential primary opponent Bernie Sanders's vote in favor of that law.

Williams, who is working on a master's degree at the University of North Carolina at Charlotte, wants all candidates -- including Bernie Sanders -- to be held accountable for their past actions and statements about racial justice.

"All the candidates who are running for president need to be held to the same kind of scrutiny in terms of the way that they have been complicit in mass incarceration and damaging communities of color across the United States," Williams said. "Bernie can get it, too. They can all get it."

In a statement, Sanders's campaign manager Jeff Weaver said that Sanders voted for the 1994 crime bill to protect provisions embedded in it that preserved the assault weapons ban and included domestic violence protections for women.

Weaver noted that Sanders criticized mass incarceration at the time that the bill was being considered.

“When this so-called crime bill was being considered, Bernie Sanders criticized its harsh incarceration and death penalty provisions," Weaver said. "Hillary Clinton, on the other hand, resorted to dog whistle politics and dehumanizing language."

"Bernie Sanders has always known jails and incarceration are not the answer," Weaver added. "Nor is heated rhetoric against young people of any race. You can’t throw vulnerable people under the bus just because it’s politically expedient.”

Correction: An earlier version of this post said Hillary Clinton told activist Ashley Williams "you're being rude." It was a guest at the fundraiser who made the comment.