Former Air Force Sergeant Steven Carrillo has already pleaded guilty in federal court in the May 2020 killing of a federal security officer in Oakland, for which he's been sentenced to 41 years behind bars. And he's pleaded guilty to killing a Santa Cruz County sheriff's deputy days later, and that case is still pending. But now we're getting a bit more of the timeline filled in of Carrillo's violent spree, inspired by the Boogaloo movement.

How Carrillo came to abandon his military career, get drawn in to the dark corners of Boogaloo groups on Facebook, and quickly escalate to committing murder, is a story we've had in dribs and drabs up until now, via various court filings and federal press releases. The Chronicle published a lengthy piece on Sunday that mostly rehashes what we already know about Carrillo's case, but does include a few new details as well as reporting from the courtroom where Carrillo was sentenced last month.

Some key details concern the involvement of four men considered accomplices in Carrillo's spree, even though they did not physically participate in his ultimate acts of violence. Those four men — 29-year-old Jessie Rush of Turlock, 23-year-old Simon Ybarra of Los Gatos, 21-year-old Kenny Miksch of San Lorenzo; and 33-year-old transient Robert Blancas — all allegedly met Carrillo online, through a Facebook group called K/alifornia Kommando, sometime around the start of the pandemic in 2020.

Rush, himself a "severely damaged" Army veteran according to court papers, formed a small militia group that he dubbed the 1st California Grizzly Scouts, and he invited several other group members to Turlock for target practice and "tactical training." And he and other Grizzly Scouts discussed the idea of pitting law enforcement against antifa groups, with the aim of inflicting harm on both, the Chronicle reports.

Experts say that Boogaloo proponents have largely been non-violent — a lot of talk and target practice and scary-looking gatherings with their Hawaiian shirts and weapons — but this case highlights how it only takes one unhinged individual to take their cues from all that violent rhetoric to have a body count.

It's not clear whether all of Carrillo's interactions with three of the men were fully conducted online, but investigators say that Ybarra, at least, met up in person with Carrillo in Los Gatos on May 27, 2020, days before the night of protest in Oakland that Carrillo would choose to use as cover for the shooting of "a fed." That fed was Homeland Security Officer David Patrick Underwood, age 53.

Ybarra allegedly watched Carrillo assemble an untraceable AR-15 style rifle that he would use in the killing, while meeting up in a gas station parking lot. And while Carrillo reached out to Ybarra the next day to entice him into joining him in Oakland, Ybarra apparently never respnded — and Carrillo ended up turning to another Grizzly Scout he'd never met offline, Robert Justus Jr., who agreed to drive the van while Carrillo took his shots. (Justus's case is still pending.)

Rush, Ybarra, Miksch, and Blancas all pleaded guilty last fall to charges that included destroying evidence — they allegedly tried to scrub their phones following Carrillo's spree — and as the Chronicle reports, a federal judge almost threw out their pleas, suggesting that the short sentences attached were insufficient. But he ultimately accepted the sentences — one year for Rush, and six months each for Ybarra and Miksch — saying that Rush's mental health and the youthful ages of the other two were mitigating factors in his decision. (It's not clear how Blancas was sentenced.)

The federal judge who accepted Carrillo's guilty plea was also reluctant to accept the 41-year plea deal, but mental illness was a factor there as well. Apparently Carrillo was diagnosed with a mental illness during his initial imprisonment in 2020 and has been taking medication ever since. The illness was not named in court records. His attorney told the court that "Each day, he becomes a little clearer about what has gone on and about the sorrow he feels."

Another detail we learn concerns how Carrillo seemed so prepared for the arrival of Santa Cruz County deputies at his home, where he ambushed them a week after the killing in Oakland. According to court documents, some of which are still sealed, it seems likely that Grizzly Scouts members were monitoring police radio in the area and alerted Carrillo that his van had been spotted and authorities were on the way.

On June 6, 2020, Carrillo allegedly shot and killed Sheriff's Sgt. Damon Gutzwiller, 38, and injured several other deputies after ambushing them and setting off an improvised explosive of some kind.

The Chronicle suggests that Carrillo has pleaded not guilty in Gutzwiller's murder, but the opposite was widely reported just a month ago — Carrillo entered a guilty plea on June 27, as reported here and elsewhere, in exchange for a life sentence without parole. It's not clear if this was a mistake in the Chronicle piece, or if Carrillo has since changed his plea.

A hearing in the Santa Cruz case is scheduled for August 26.

Previously: Former Air Force Sergeant Pleads Guilty to Murdering Santa Cruz Deputy