Last week, Gizmodo reported that Facebook news curators have a huge amount of power to decide what news topics trend. This week, the publication dropped another bombshell from a former staffer who claimed the social media giant intentionally suppressed conservative news while artificially promoting other causes like Black Lives Matter.

While this kind of biases exists in all newsrooms, it’s particularly troubling on Facebook because of the site’s claim that trending stories merely represent “topics that have recently become popular on Facebook.” If Gizmodo’s reports are true, then that statement clearly isn’t.

The former Facebook staffer who spoke with Gizmodo about the alleged conservative suppression identified themselves as a conservative, one of the few on the team, kept a running tally of all the conservative topics that were suppressed on the site. Whether the suppression was the result of intentional biases or not, the former staffer says that they saw the effects.

“I believe it had a chilling effect on conservative news,” the individual said.

Another former news curator said that Facebook would also artificially “inject” stories into the trending feed, including stories about the Black Lives Matter movement.

“Facebook got a lot of pressure about not having a trending topic for Black Lives Matter,” the individual said. “They realized it was a problem, and they boosted it in the ordering. They gave it preference over other topics. When we injected it, everyone started saying, ‘Yeah, now I’m seeing it as number one’.”

Why is that a problem? As reporter Michael Nunez points out in Gizmodo, Black Lives Matter was a movement that seemed to begin, or at least draw much of its momentum, from Facebook. That means the site’s meddling could have indirectly driven a major political cause.

Soon after it was released, this controversial report began to pop up in (you guessed it) Facebook’s trending news section. You can bet there are more big revelations like it about Facebook’s inner-workings coming our way soon.

UPDATE: Facebook responded yesterday by saying, “There are rigorous guidelines in place for the review team to ensure consistency and neutrality,” the spokesperson added. “These guidelines do not permit the suppression of political perspectives. Nor do they permit the prioritization of one viewpoint over another or one news outlet over another. These guidelines do not prohibit any news outlet from appearing in Trending Topics.”