Steven Carrillo, the man suspected of killing a Santa Cruz, California, sheriff's sergeant this month, has now been charged in the May slaying of a federal officer in Oakland, authorities announced Tuesday.
Authorities had said earlier they were investigating possible links between the two shootings.
Carrillo, a 32-year-old active duty Air Force sergeant, was first arrested for allegedly gunning down Santa Cruz Sheriff's Sgt. Damon Gutzwiller in Ben Lomond, California, on June 6.
Gutzwiller, a 38-year-old husband and father, had been responding to a call about a suspicious van and saw someone with guns and bomb-making devices, sheriff's officials said.
The van driver fled, and when deputies tried to follow, they were ambushed with gunfire and multiple improvised explosives, officials said. Gutzwiller was killed and another officer was injured.
Carrillo allegedly carjacked residents at gunpoint before he was captured, sheriff's officials said.
On Tuesday, David Anderson, U.S. Attorney for the Northern District of California, announced that Carrillo is accused of killing Patrick Underwood about one week before Gutzwiller was killed.
On the night of May 29, Underwood, a 53-year-old federal law enforcement officer, was shot dead while providing security at a federal building in Oakland, near a Black Lives Matter protest. A second officer was shot and survived.
The FBI launched a manhunt and released photos of the van they believed the shooter was driving. Authorities said Tuesday they believe the same van was used in the Oakland and Ben Lomond shootings.
Carrillo allegedly shot Underwood while his alleged accomplice, Robert Justus Jr., 30, drove the van, Anderson said.
FBI Special Agent in Charge of the San Francisco field office, John Bennett, said Tuesday, "We believe Carrillo and Justus chosen this date because the planned protest in Oakland provided an opportunity for them to target multiple law enforcement personnel."
"They came to Oakland to kill cops," he said.
Oakland interim police chief Susan Manheimer said over 500 officers were on the ground in the city.
Authorities also claim Carrillo used "his own blood” to write phrases associated with the Boogaloo movement on a car he allegedly carjacked.
"The 'Boogaloo' term is used by extremists to reference a violent uprising or impeding war in the United States," Anderson said.
Carrillo is charged with murder and attempted murder while Justus, who was arrested June 11, is charged with aiding and abetting, prosecutors said. Carrillo also faces state charges in the Gutzwiller case.
Justus made his initial appearance Monday and is due to return to court Friday. Carrillo has not entered a plea for the state charges and has not yet appeared in federal court.
Last week, while the search for Underwood's killer was ongoing, Underwood's sister, Angela Underwood Jacobs, testified at the House Judiciary Committee hearing on police reform.
"Patrick was a good man who only wanted to help others and keep his community safe," she testified.
"I want to ensure the memory of my brother, Patrick, is a catalyst against injustice, intolerance and violence of any kind," she said. "Please do not let my brother Patrick's name go in vain."
ABC News' Leah Larosa and Bonnie Mclean contributed to this report.
This report was featured in the Wednesday, June 17, 2020, episode of “Start Here,” ABC News’ daily news podcast.
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