Thirteen people were killed in a shooting at the Borderline Bar & Grill in Thousand Oaks, including the shooter and Helus.
Ventura County Sheriff's Office Capt. Garo Kuredjian said late Wednesday that it was still "a very active scene". He died at a hospital after being shot numerous times. Dean said Helus undoubtedly saved lives by going in to confront the gunman.
Speaking at press conference in the wee hours of Thursday, a sheriff said that around a dozen other people had been injured.
A police officer is among the wounded in the mass shooting at the Borderline bar in the city of Thousand Oaks near Los Angeles, reports say.
The attack on the bar - a college favorite and was hosting a country music event - was the nation's deadliest shooting since 17 students and teachers were killed at a Parkland, Florida, high school nine months ago.
"Ron ... gave his all and tonight, he died a hero because he went in to save lives", Dean said. Others jumped over chairs and broke windows to get out of the bar.
It was the second mass shooting in less than two weeks, after a gunman killed 11 Jewish worshipers at a Pittsburgh synagogue on October 27.
The killer was identified as Ian David Long, a 28-year-old veteran who authorities said had an episode of erratic behavior last spring that was thought to be post-traumatic stress disorder because of his military background.
ABC Reporter Marc Brown said: "We are hearing that some of the people who were at Borderline, were also at the Route 91 Harvest Festival in Las Vegas, scene of the worst mass shooting in modern U.S. history". But most agree that there was a shooting and many people fled the bar and grill.
Federal Bureau of Investigation data suggests that Thousand Oaks is the third-safest city in America.
The father of one patron told CBS L.A. his daughter told him the gunman "knew what he was doing" and came in "with a objective". Helus was a 29 veteran of the force who had planned to retire in the next year.
Holden Harrah, a young man who saw the incident, cried as he told CNN that a place where he goes every week to have fun with friends had been a scene of carnage.
"When the officers went in and made re-entry, they found him already deceased", Dean said, according to ABC 6. "They would go fishing up in the Sierras together".
"I tried to get as many people to cover as I could", Knapp said.
Cody Coffman had plans to join the Army, his father, Jason, told reporters Thursday.