Steven Carrillo, the Ben Lomond resident charged with killing one Santa Cruz County sheriff’s deputy and injuring another, was also the shooter of two law enforcement officers in Oakland last month, U.S. Attorney Dave Anderson has alleged.

Millbrae resident Robert Justus Jr. drove a white van past a federal courthouse in Oakland on May 29, while Carrillo shot two security officers—David Patrick Underwood, who died, and one of Underwood’s colleagues, who was injured—out of the van’s open sliding passenger-side door, Anderson said in a press conference.

Carrillo used a privately made machine gun, with no markings or serial number, that had a silencer on the barrel, Bureau of Alcohol, Tobacco, Firearms and Explosives Special Agent in Charge Patrick Gorman added.

Though there was a protest in Oakland that day, officials said the two men were using the demonstration over the death of George Floyd at the hands of Minnesota police officers as cover. “The planned protests in Oakland provided an opportunity for them to target multiple law enforcement personnel and avoid apprehension in the large crowds attending the demonstrations,” FBI Special Agent in Charge Jack Bennett said.

“To be clear, Carrillo elected to travel to Oakland to conduct this murder and take advantage of a time when this nation was mourning the killing of George Floyd,” Bennett added. “There is no evidence that these men had any intention to join the protest in Oakland, as some media have asked. They came to Oakland to kill cops.”

In a vehicle registered to Carrillo, detectives found a ballistic vest with a patch on it, Anderson said. The patch had an American-style flag, but in the area where the stars would be there was instead a picture of an igloo. In place of one of the flag’s stripes was a Hawaiian-style motif, Anderson said.

Additionally, Carrillo appeared to use his own blood to write phrases in a car that he carjacked. The motif and the phrases he wrote—”Boog,” “I became unreasonable,” and “Stop the duopoly”—are thought to be associated with the Boogaloo Bois, a newly formed group of violent extremists with anti-government beliefs.

“The complaint alleges that the patch and the phrases written by Carrillo are associated with the so-called Boogaloo movement,” Anderson said. “The term is used by extremists to represent a violent uprising or impending civil war in the United States.”

In addition to facing several charges in the Ben Lomond shooting, Carrillo has now been charged with murder and attempted murder in the Oakland shooting. Carrillo, who has been in state custody, will be brought into federal custody, Anderson said. Justus has been charged with aiding and abetting murder and attempted murder, he said.

More than a week after the May 29 Oakland shooting, a caller in Santa Cruz County reported seeing a suspicious-looking white van owned by Carrillo on June 6. When deputies arrived at Carrillo’s Ben Lomond home, a shootout ensued, in which Carrillo killed Sgt. Damon Gutzwiller and injured Deputy Alex Spencer.

Carrillo fled on foot and via carjackings before being tackled by a neighbor, and he was arrested shortly thereafter.