A Vice News investigation has found that Twitter is shadow-banning, or clandestinely blocking, prominent conservatives on its platform.

Notably, House Freedom Caucus members such as Rep. Mark Meadows, R-N.C.,  Rep. Jim Jordan, R-Ohio, Rep. Matt Gaetz, R-Fla., and others have been shadow-banned from the platform. So has GOP Chairwoman Ronna McDaniel.

The investigation also found that prominent Democrats had no issue with Twitter’s supposed automated filter.

Democrats are not being "shadow banned" in the same way, according to a VICE News review. McDaniel’s counterpart, Democratic Party chair Tom Perez, and liberal members of Congress — including Reps. Maxine Waters, Joe Kennedy III, Keith Ellison, and Mark Pocan — all continue to appear in drop-down search results. Not a single member of the 78-person Progressive Caucus faces the same situation in Twitter’s search.

Conservative legislators and activists responded to the shadow-ban investigation, demanding answers from Twitter executives.

Vice presented the evidence of systematic bias to a Twitter spokesperson, who responded: “We are aware that some accounts are not automatically populating in our search box and shipping a change to address this.”

Then Twitter was asked to account for the obvious partisan discrepancy, given that the system appears to target only conservatives. “I'd emphasize that our technology is based on account *behavior* not the content of Tweets,” the spokesperson added.