(CNN) Sen. Amy Klobuchar's presidential campaign said Friday that it was returning money donated by a former prosecutor who has faced sharp public criticism for her role in the Central Park Five rape case, according to a campaign spokesperson.

"The campaign shouldn't have accepted this contribution and we're returning it," the spokesperson told CNN.

After the series debuted, Fairstein stepped down from Vassar College's Board of Trustees, among other positions, due to the resulting public backlash, according to a letter from the college's president.

The news of Fairstein's contribution to Klobuchar's campaign comes as the Minnesota Democrat more than doubled her fourth-quarter fundraising total from the previous quarter but lags significantly in support from nonwhite voters. The senator was the top choice of 0% of black people in South Carolina in a Quinnipiac University poll released in mid-November , a survey that covered 18 candidates who were then running for president, and 1% of nonwhite voters in Nevada in a CNN poll released in late September.

Klobuchar served two terms as a county attorney for Hennepin County in Minnesota. the most populous county in the state, from 1999 to 2007, and has been pressed during the campaign to defend her record as a prosecutor over what critics have called "tough on crime" policies.

In March, The Washington Post reported on Klobuchar's unwillingness to prosecute police involved in killings of black men during her tenure. Around the same time, American Public Media reported that Klobuchar frequently sided with the police over misconduct charges. Of her tenure, she was quoted as telling The Washington Post that "kids that were killed by gangsters" were the kinds of cases she focused on, and telling American Public Media that "in that job I tried to put myself in other people's shoes to try to do the right thing."

That same month, the senator said on CNN's "State of the Union" that she had worked against racial disparities during her time in office, after being asked about a Minnesota Public Radio report from her time as county attorney. The report found inequality in law enforcement, particularly against African Americans.

Sen. Elizabeth Warren of Massachusetts has also been the recipient of some form of help from Fairstein. The former prosecutor hosted a Warren fundraiser in New York during her 2012 Senate run, according to The Guardian.

CNN reached out to the Warren campaign for comment on Fairstein's exact role in the fundraiser, but has not yet received a reply.

In response to the controversy last year, Warren's presidential campaign disavowed Fairstein's support.

"This was in 2012 but it was wrong. Linda's record is troubling and highlights how the criminal justice system has caused irrevocable harm to Black communities. Part of deciding to run our presidential campaign the way we are is the decision to say Elizabeth is not going to give special access to high-dollar donors through closed-door fundraisers," Warren spokeswoman Gabrielle Farrell said in a statement to CNN.