Three far-right extremist groups joined forces and “orchestrated a plan” in advance of the January 6th insurrection at the U.S. Capitol that left dozens injured and five dead, according to accusations levied by prosecutors in court filings on Tuesday.

While arguing that Kelly Megs, the leader of the anti-government militia the Oath Keepers, should remain in detention while awaiting trial, lawyers at the Department of Justice submitted Facebook messages between Megs and associates from December 2020. In one message from December 19th, Megs explains that the Oath Keepers, the Proud Boys, and the Florida 3%ers have create “an alliance” and will “work together and shut this sh*t down.” Megs was apparently referring to the possibility of counter-protests planned for January 6th.

In another message, three days later, Megs revealed that he had made “contact” with the Proud Boys and they would serve as a “force multiplier” at the Stop the Steal rally. He outlined specific tactical plans. The Proud Boys and Oath Keepers would sandwich any Antifa contingent in the crowd and attack them from the front and the back, or as Megs put it, “F***ing crush them for good.”

Another three days later, on Christmas, Megs shared what prosecutors call a “provisions list” with a member of the Proud Boys: “DC is no guns. So mace and gas masks, some batons. If you have armor that’s good.”

The next day, Megs told an associate that then-President Donald Trump would soon “use the emergency broadcast system” to “claim the insurrection act.” When the associate asked when, Megs said “wait until the 6th when we are all in DC to insurrection.”

So far, approximately 400 people have been charged in connection with the January 6th violence. Several members of the Proud Boys, the Oath Keepers, and the Florida 3%ers are among those arrested. But the revelations in Tuesday’s court filings are the first indication prosecutors have provided that multiple extremist groups coordinated in advance of the attack.

On Wednesday, The New York Times reported that the Department of Justice is weighing sedition charges against members of the Oath Keepers, which is the crime of conspiring to overthrow the government. A sedition charge has not been successfully prosecuted in over two decades.