Uber Technologies Inc’s Chief People Officer Liane Hornsey resigned on Tuesday, Chief Executive Dara Khosrowshahi said, following an investigation into how she handled allegations of racial discrimination at the ride-hailing firm.

The resignation comes after Reuters contacted Uber on Monday about the previously unreported investigation into accusations from anonymous whistleblowers that Hornsey had systematically dismissed internal complaints of racial discrimination.

Hornsey is head of Uber’s human resources department and one of the firm’s top spokespeople on diversity and discrimination issues. She has been in the role for about 18 months.

Khosrowshahi did not give a reason for her departure but praised her in an email to employees which was seen by Reuters as “incredibly talented, creative, and hard-working.”

Hornsey acknowledged in a separate email to her team at Uber, also seen by Reuters, 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.