Authorities announced Friday that Ventura County police Sergeant  Ron Helus, who was counted among the 12 victims of the Thousand Oaks mass shooting, died as a result of friendly fire.

Though suspect Ian David Long, 28, struck Helus five times, the county medical examiner said it’s not only possible that he would’ve survived those injuries but revealed that the sixth and fatal bullet—which struck Helus in the heart—was fired by a fellow California Highway Patrol officer, the Los Angeles Times reported.

“This was a dynamic, chaotic event that led to a very brief, but furious gun battle between the killer and the lawmen,” Ventura County Sheriff Bill Ayub said, adding that Long is still to blame for the casualties associated with the November 7 shootout. “He alone created the violence, and he alone bears responsibility for his course of action.”

The Ventura County Star noted that this is the second major update from law enforcement in the past two weeks. On November 27, Ayub and FBI officials said a motive remains unclear but that there’s no evidence Long was radicalized.

Long was reportedly armed with a knife and a .45-caliber Glock handgun when he entered the Borderline Bar and Grill and opened fire, killing 11 and wounding two, including Helus, before taking his own life.

Helus and other law enforcement arrived at the scene within minutes and were met by a barrage of bullets. Ayub said Helus and a CHP officer simultaneously entered the bar and, at some point, Helus was caught between the officer and gunman.

CHP’s coastal division chief LD Maples said they revealed the coroner’s finding to the officer on Tuesday.

“He had no clue it was coming, was as surprised as all of us,” Maples told CNN. “He’s devastated. He’s a consummate professional, well-trained, military background.”

Authorities are working to analyze digital media left behind by Long—an undertaking they say will take some time.

[Featured image: Ron Helus/Ventura County Sheriff’s Department]