Liane Hornsey resigned as Uber's chief people officer.Uber Uber's Chief People Officer Liane Hornsey resigned Tuesday amid a company investigation into how she handled allegations of racial discrimination at the ride-hailing startup. An Uber spokesman confirmed Tuesday night that Hornsey had resigned after Reuters contacted the company about anonymous accusations she had systematically dismissed internal complaints of racial discrimination. Hornsey, who led Uber's human resources department, joined the company in January 2017. An email Uber CEO Dara Khosrowshahi sent to employees Tuesday announcing Hornsey's resignation didn't reveal a reason for her departure. In his email, obtained by Reuters, Khosrowshahi called Hornsey "incredibly talented, creative, and hard-working" and "a valuable member of my leadership team." In a separate email to her team, also obtained by Reuters, Hornsey also gave no reason for her departure but said it "comes a little out of the blue for some of you, but I have been thinking about this for a while." Of all tech companies, Uber likely has the most to prove in the diversity department. Last year it faced a reckoning that saw an exodus of high-level executives, five federal investigations and a damning internal investigation led by former US Attorney General Eric Holder. The unraveling began after former Uber engineer Susan Fowler wrote a blog post alleging a chaotic corporate culture, gender bias and workplace sexual harassment. In April, Uber issued its second-ever diversity report, which showed the startup saw a slight increase in the number of women and people of color in its workforce. "Diverse, inclusive teams are a company's greatest asset: they challenge assumptions, drive innovation, and we believe strongly they are a competitive advantage," Hornsey wrote in a blog post announcing the diversity report. "We have made meaningful progress over the last year, but we still have a lot of work to do to increase representation of women and underrepresented groups." Hornsey couldn't immediately be reached for further comment. Pranesh Anthapur, Uber's vice president of human resources, will replace Hornsey on an interim basis. CNET's Dara Kerr contributed to this report. Cambridge Analytica: Everything you need to know about Facebook's data mining scandal. iHate: CNET looks at how intolerance is taking over the internet.