Today, former Facebook partnerships manager Mark Luckie published an internal memo that was sent to his co-workers on his last day at Facebook earlier this month, calling out pervasive discrimination issues within the company. The note argues that Facebook has a “black people problem” that involves the mistreatment of black employees. He cites incidents where managers or colleagues called their co-workers “hostile” or “aggressive,” and others where campus security gave extra scrutiny to black employees.

“In some buildings, there are more ‘Black Lives Matter’ posters than there are actual black people,” he writes. “Facebook can’t claim that it is connecting communities if those communities aren’t represented proportionately in its staffing.”

“I’ve lost the will and the desire to advocate on behalf of Facebook.”

Luckie goes on to detail how the company’s HR department often protects managers — not the people filing complaints. “Black staffers at Facebook know that by raising our voices we risk jeopardizing our professional relationships and our career advancement,” he says. “As much as we’d like to convince ourselves these are minor inconveniences, they continue to eat away at us and affect our work.”

Luckie says these issues and others led to him leaving the company to focus on creating a podcast. Facebook has made minor improvements regarding diversity in the workplace. The company said earlier this year that black employees represented 8 percent of business and sales roles, while only 1 percent of technical roles are filled by black employees, and black employees only represent 2 percent of leadership roles. Facebook says it has “so much more still to do across the board,” and it’s focusing on diversity.

In his note, Luckie praises the efforts but says they don’t go far enough and that the real issues come down to company culture overall. “To continue to witness and be in the center of the systematic disenfranchisement of underrepresented voices, however unintentional, is more than I’m willing to sacrifice personally,” Luckie writes. “I’ve lost the will and the desire to advocate on behalf of Facebook.”

In an emailed comment to The Verge, Facebook spokesperson Anthony Harrison says:

“Over the last few years, we’ve been working diligently to increase the range of perspectives among those who build our products and serve the people who use them throughout the world. The growth in representation of people from more diverse groups, working in many different functions across the company, is a key driver of our ability to succeed. We want to fully support all employees when there are issues reported and when there may be micro-behaviors that add up. We are going to keep doing all we can to be a truly inclusive company.”

Facebook is already facing many of these same criticisms from outside the company. Color of Change, an online racial justice group, has called for the company to publicly release a civil rights audit and fire global public policy vice president Joel Kaplan, who has drawn criticism over his support for conservative causes. The group will meet with Facebook executives on Thursday to discuss how Facebook can address “systemic problems on the platform.”

Update 11/27, 1:59 PM ET: Updated to include Facebook’s comment.