Four members of an armed right-wing group linked to the anti-government “boogaloo” movement have been charged with conspiring to destroy evidence related to the fatal shooting of a Federal Protective Service officer and the wounding of another in Oakland, Calif., last May, prosecutors announced Friday.

A federal grand jury indictment says members of the Northern California-based Grizzly Scouts tried to cover for one of their own after he allegedly gunned down the officers, deleting chat histories that included a message reading, “Dudes i offed a fed.”

Jessie Alexander Rush, 29, Robert Jesus Blancas, 33, Simon Sage Ybarra, 23, and Kenny Matthew Miksch, 21, are accused of conspiracy to destroy records and destruction of records in official proceedings. Rush faces an additional count of obstruction of official proceedings, and Blancas is charged with an additional count of destruction of records in official proceedings.

Prosecutors said the men belonged to a Facebook group named “/K/alifornia Kommando” and would meet in person for firearms training and other activities. According to the indictment, the Facebook group’s description read, “they say the west won’t boog” — a phrase, prosecutors say, that refers to the boogaloo movement, a loose collection of anti-government extremists who agitate for civil war.

All four men remained in federal custody over the weekend. If convicted, each could be sentenced to up to 20 years in prison. A lawyer for Blancas declined to comment on the case. Attorney information for the other defendants wasn’t immediately available.

The indictment comes as domestic terrorism incidents have soared in the United States and law enforcement agencies face pressure to crack down on far-right extremists after the deadly attack on the U.S. Capitol in Washington on Jan. 6.

The charges in this case are the latest targeting alleged adherents of the boogaloo movement, whose followers became increasingly visible at protests after the death of George Floyd in Minneapolis police custody on May 25, 2020. Numerous self-proclaimed boogaloo followers have been arrested in attacks or in connection with alleged plots in recent months, among them three alleged members in Nevada who were accused of plotting to use molotov cocktails to spark violence at a rally over Floyd’s death.

The shooting of the agents in Oakland happened on May 29 outside a federal courthouse during a racial justice demonstration in the city’s downtown.

According to investigators, Steven Carrillo, a 32-year-old Air Force staff sergeant, was using the gathering as cover when he fired an assault rifle at a guard post from a moving vehicle. The shots killed Officer David Patrick Underwood, 53, and seriously injured a second officer.

On June 6, authorities tracked Carrillo to a property in Ben Lomond, Calif., more than 70 miles from Oakland. As deputies surrounded the property, Carrillo sent a flurry of WhatsApp messages to members of the Grizzly Scouts in a group chat labeled “209 Goon HQ,” according to the indictment.

One message told the members to “kit up and get here” and to “take them out,” according to the indictment. Another allegedly read: “Dudes i offed a fed.”

Rush, whom prosecutors described as “commanding officer” of the Grizzly Scouts, told Carrillo to “factory reset” his phone, deleting its stored communications, according to the indictment.

Carrillo was arrested that afternoon after a gun battle that left one officer from the Santa Cruz County Sheriff’s Office dead and others injured. When authorities searched the vehicles used by Carrillo, police said, they found a boogaloo patch, ammunition, firearms, bombmaking equipment and three boogaloo-related messages scrawled in blood: “I became unreasonable,” “Boog” and “Stop the duopoly.”

Carrillo pleaded not guilty to counts of murder and attempted murder in federal and state courts in connection with the shootout during his arrest and the Oakland shooting. A lawyer representing Carrillo in federal court declined to comment on his case and the allegations in Friday’s indictment.

While Carrillo was being processed last summer, the four other Grizzly Scouts now indicted deleted all the “209 Goon HQ” chat logs from their phones, the indictment says, and reconnected on “an alternative communications application.” There, they turned on a “disappearing messages” function, automatically erasing their chats after a certain period, according to prosecutors.

Blancas, described in the indictment as a “1st lieutenant” in the Grizzly Scouts and responsible for security and intelligence, also deleted 20 files related to the armed group from a Dropbox account, prosecutors said. The materials included documents related to the group’s structure, a nondisclosure agreement, a liability release waiver, and “a scorecard to assess members of the Grizzly Scouts with respect to combat, firearms, medical, and other training,” according to the indictment.

Afterward, the members “repeatedly confirmed with one another that they had destroyed evidence relating to the Grizzly Scouts,” prosecutors said.

In August, FBI agents searched properties connected with the four defendants. They confiscated assault rifles, pistols, body armor, ammunition, and electronic devices, according to the indictment.

Rush, Ybarra and Miksch made their initial appearances in federal court this week.

Blancas already was in federal custody after being arrested in November on a charge of enticement of a minor to engage in sexual activity, records show. Agents who seized his electronic devices said they found child pornography and sexually explicit messages with a 15-year-old girl, according to records. He entered a plea of not guilty in December. His attorney declined to comment on the allegations.