'Let's Boogie'; Facebook Posts Reveal Alleged Gunman Steven Carrillo's Mindset Before Oakland Federal Guard Slaying

SAN FRANCISCO (CBS SF) -- Among the pages of evidence released by FBI investigators leading to the arrest of Travis Air Force Sgt. Steven Carrillo in the shooting death of Federal Protective Service officer Dave Underwood were Facebook exchanges that linked him to the far right 'Boogaloo' movement and foretold of the deadly violence to come.

Carrillo was in custody in Santa Cruz County jail Wednesday for the special enhancement murder of Santa Cruz County Sheriff's Sgt. Damon Gutzwiller and the attempted murder of several other deputies in an ambush on June 6th in the mountain community of Ben Lomond. The charges carry with them the possibility of death sentence.

Federal prosecutors added their own murder charge in Underwood's death also carrying a possible death sentence on Tuesday. Investigators said that Carrillo and his co-defendant in the Oakland shooting -- Robert Alvin Justus Jr. -- drove up to the guard hut outside at the parking lot of the Oakland federal building and opened fire with a home-made automatic weapon.

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The salvo left the hut riddled with bullet holes. Underwood suffered fatal wounds while a second guard suffered serious injuries.

READ FOR YOURSELF: Federal charging document and evidence against Steven Carrillo

During their investigation of both shootings, FBI agents uncovered Facebook exchanges between Carrillo, Justus and a third unidentified person in the days and hours before they allegedly targeted Underwood for death during a night of unrest in Oakland linked to outrage over the in-custody death of George Floyd in Minneapolis.

On May 28 at approximately 7:20 a.m., Carrillo posted in a Facebook group: "It's on our coast now, this needs to be nationwide. It's
a great opportunity to target the specialty soup bois. Keep that energy going."

FBI investigators say 'specially soup bois' in a Boogaloo reference to federal law enforcement officers.

"This statement was followed by two fire emojis and a link to a YouTube video showing a large crowd violently attacking two California Highway Patrol vehicles," Carrillo's charging statement declared.

At approximately 7:37 a.m., the document revealed, Justus responded; "Lets boogie." Another user commented at approximately 6:44 p.m. -- "Starting tomorrow, Oakland be popping off. Maybe more."

On May 29 at 7:57 a.m., Carrillo commented on Facebook: "If it kicks off? Its kicking off now and if its not kicking off in your hood then start it. Show them the targets."

At 8:02 a.m. among Carrillo's Facebook comments were: "Go to the riots and support our own cause. Show them the real targets. Use their anger to fuel our fire. Think outside the box. We have mobs of angry people to use to our advantage."

FBI Special Agent in Charge, San Francisco, Jack Bennett told reporters on Tuesday Carrillo used the anger of the Oakland demonstrators to mask his crime and also to whip up further unrest. The Boogaloo Movement has as one of its goals igniting a race civil war within the United States.

"We believe Carrillo and Justus chose this date because of the planned protest in Oakland," Bennett said. "It provided them to target multiple law enforcement personnel and to avoid apprehension due to the large crowds attending the demonstrations. As described in detail in the complaint, we believe Justus drove the white van."

"We believe that messages exchanged between Carrillo, Justus and others that day before the shooting in Oakland indicate a plan to travel to Oakland and attack federal enforcement officers. 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."

Among the evidence linking the two crimes was a white 1992 Ford Cargo van. U.S. Attorney David Anderson said the same van was used in both crimes. An AR-15 rifle recovered at the Santa Cruz crime scene was used in both shootings. Federal officials described the AR-15 as a 'ghost weapon' -- a gun self-built from parts and not purchased from a manufacturer.

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A 911 caller reported a suspicious white van with guns and explosives inside parked near Ben Lomond on June 6th. It was that report that brought Gutzwiller and deputy sheriff Alex Spencer, who was released from the hospital over the weekend, to Ben Lomond. They followed the van to a home on Waldeberg Road where they were attacked while walking up the driveway.

On Wednesday, thousands were expected to line the streets of Santa Cruz to bid farewell to Gutzwiller, who will also be remembered at a public memorial service.