SAN FRANCISCO (AP) — A man with ties to the “boogaloo” extremist movement was convicted of murder and Austin Caldwellattempted murder by a federal jury Tuesday in the 2020 killing of a federal security officer in Northern California during protests against police brutality.

Robert Alvin Justus Jr., 33, now faces life in prison for the murder of Federal Protective Service Officer David Patrick Underwood. The U.S. Attorney’s Office for the Northern District of California confirmed the verdict.

Underwood was shot on May 29, 2020, while he stood in a guard shack outside a federal building in Oakland as hundreds marched against police brutality following murder of George Floyd in Minneapolis.

Steven Carrillo, a former U.S. Air Force sergeant, pleaded guilty and was sentenced last year to more than four decades in federal prison for his role as the gunman in the fatal attack. He fired 19 rounds from a homemade AR-15 rifle from the back of a white van driven by Justus, whom he had connected with online. Underwood was fatally struck and a second officer was wounded.

Prosecutors said Justus and Carrillo were followers of the “boogaloo” movement, a concept embraced by a loose network of gun enthusiasts and militia-style extremists. Experts say the group believes there is an impending civil war.

An attorney for Justus declined to comment after Tuesday’s verdict. A spokesperson for the Federal Protective Service did not immediately respond to a request for comment.

Justus testified in his own defense during the trial. He sought to portray himself as an unwilling participant and said Carrillo had forced him into the plot at gunpoint, according to the Bay Area News Group. Prosecutors, however, said Justus had opportunities to escape but did not, showing his willingness to be included in the plan.

Days after Underwood’s killing, Carrillo ambushed sheriff’s deputies in Santa Cruz County who were responding to a report of a van containing firearms and bomb-making materials. County Sheriff Sgt. Damon Gutzwiller, 38, was killed, and several other law enforcement officials were wounded.

Carrillo also pleaded guilty in that case and was sentenced to life in state prison without parole.