NEW YORK (NewsNation Now) — The New York City Police Department has opened an internal investigation after a data leak suggests that some active members may have ties to the Oath Keepers, a far-right, anti-government militia.

The leak came from an anonymous hacker. It included emails and membership information that appear to show at least two active members of the NYPD are also Oath Keepers.

The Oath Keepers are known as being a key player in the attack on the U.S. Capitol earlier this year. So far, 18 members have already faced federal conspiracy charges.

New York City Mayor Bill de Blasio issued a firm statement Thursday regarding the new information.

“Anyone who’s involved in an organization that’s supporting violence against the people, against the government or racial and ethnic violence — they don’t belong on the NYPD.”

Chief Juanita Holmes with NYPD Patrol Bureau said the department is taking the issue seriously.

“Whether it’s related to terrorism, things of that nature, intel, we follow the lead,” Holmes said. “So if we receive an allegation of someone being affiliated with those particular groups, then that would definitely automatically trigger a thorough investigation.”

The mayor’s office and the NYPD are stressing that these are, allegedly, two members of a force of 36,000 uniformed officers and hundreds of civilians. The NYPD prohibits members of the force from associating with groups “reasonably believed” to be criminal organizations.