Ventura County Sheriff Sgt. Ron Helus was used to running toward danger.
As a 29-year veteran of the department and a member of its SWAT team for several years, Helus was one of the first officers to rush inside the Borderline Bar and Grill in Thousand Oaks, California, late Wednesday to answer the call of an active shooter.
He exchanged gunfire amid the chaos, authorities said, and was struck multiple times before another officer dragged him away from the line of fire. He later died at the hospital.
Sheriff Geoff Dean choked back tears during an early-morning news conference, noting how Helus — who had a wife and son — risked his life when he arrived within three minutes of the first reports of gunfire.
Eleven others inside were killed, but officials feared the death toll could have been higher if Helus hadn't intervened. The gunman is believed to have killed himself inside the venue, Dean said.
Helus "gave his all, and tonight, as I told his wife, he died a hero," Dean said. "He went in to save lives, to save people."
Dean added that he would often work out with Helus at the gym, and he was about a year away from retirement.
Police received reports at about 11:20 p.m. PT (2:20 a.m. ET Thursday) for a shooting at the Borderline, a country western bar packed with patrons during a college night for people 18 and older.
Witness Matthew Wennerstrom told NBC Los Angeles that the shooter was dressed in "all black" and armed with a handgun when he began shooting. Patrons tried to flee out of his path as he made his way to the bar.
"He didn't say anything, at least not that we could hear," Wennerstrom said. "Everyone was just trying to get out."
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Helus — trained to enter a building when there is a report of an active shooter — went inside, and was met with gunfire. He exchanged bullets with the shooter, Dean said.
"He was willing to sacrifice his life for the sake of others," Dean said on "Today." "He ran into danger — he didn't walk."
Helus, 54, had a firearms training business in Ventura County, offering instruction on how to use and maintain various types of guns and the laws for carrying in California. On his website, Helus said he teaches in the Ventura County Sheriff's Office, which he joined in 1989.
His personal Facebook page includes photos of him fishing and enjoying the outdoors along the San Joaquin River.
"He was a cop's cop," Ventura County Sgt. Eric Buschow said on MSNBC. "He's the guy that if you were the victim of a crime, he's the guy you'd want investigating it, because he'd go to every length to find the person responsible."
A motorcade along the 101 Freeway led Helus' body from the hospital to the Ventura County Medical Examiner's Office in Ventura.