Uber Chief People Officer Liane Hornsey has resigned yesterday following an investigation into how she handled allegations of racial discrimination at the ride-hailing firm.

The resignation comes after an investigation into accusations from anonymous whistleblowers that Liane Hornsey and one of the firm's top spokespeople on diversity and discrimination issues, had systematically dismissed internal complaints of racial discrimination.

Hornsey was head of Uber's human resources department and one of the firm's top spokespeople on diversity and discrimination issues. She had been in the role for about 18 months having joined in January 2017.

Pranesh Anthapur, Uber's vice president of human resources, will replace Hornsey on an interim basis.

As per Reuters, Hornsey acknowledged in a separate email to her team at Uber that her exit "comes a little out of the blue for some of you, but I have been thinking about this for a while."

She also gave no reason for her resignation and has not responded to requests for comment about the investigation.

The allegations against her and Uber's human resources department more broadly were made by an anonymous group that claims to be Uber employees of color. They alleged Hornsey had used discriminatory language and made derogatory comments about Uber Global Head of Diversity and Inclusion Bernard Coleman, and had denigrated and threatened former Uber executive Bozoma Saint John, who quit the company in June.

The group also added that complaints filed to Uber's anonymous tip line were often left unresolved or were dismissed, especially if they dealt with issues of race. It also accused the company of ignoring a board-approved recommendation by former U.S Attorney General Eric Holder that its head of diversity report directly to the company's CEO or COO.

Meanwhile, Chief Executive Dara Khosrowshahi in an email to employees described her as "incredibly talented, creative, and hard-working." 

The email read, “In her time at Uber, she's accomplished a lot: releasing our first-ever diversity report; ushering in equal pay for all employees; hiring our new Chief Diversity & Inclusion Officer; revamping our recruiting and hiring processes to reduce bias, and greatly expanding our employee resource groups (ERGs). The list goes on…

Liane is incredibly talented, creative, and hard-working. She's been a valuable member of my leadership team and I wish her nothing but the best."

Dara, however, gave no reason for her departure. Uber however in a statement said that the complaints had been properly investigated.

"We are confident that the investigation was conducted in an unbiased, thorough and credible manner, and that the conclusions of the investigation were addressed appropriately," it said.