Sgt. Ron Helus had been set to retire in the next year from the Ventura County, California Sheriff's Office when, responding late Wednesday to a call of a shooting, he walked into the Borderline Bar & Grill.
Ventura County Sheriff Geoff Dean says a neighbor reported loud noises coming from Long's house in April and that deputies found a man "acting a little irrationally".
There were roughly 200 people in the bar for a popular weekly "College Country" night, police said.
Unconfirmed reports say the shooter is still at large and that police are still working to secure the scene at the Borderline Bar & Grill. Hindustan Times delivers the news across all social media platforms, on the web, and at your doorstep.
The 28-year-old left as a corporal in March 2013 and recently was living with his mother in the Los Angeles suburb of Thousand Oaks.
"He was hard-working, he was totally committed, he gave his all and, tonight, as I told his wife, he died a hero", Dean said at a press conference early Wednesday. "But I've learned, it doesn't matter what community you're in, it doesn't matter how safe your community is".
Using a smoke bomb and a handgun, a hooded Marine combat veteran dressed all in black opened fire during college night at a country music bar in Southern California, killing 12 people and sending hundreds fleeing in terror before apparently taking his own life, authorities said Thursday. "He's taken many young lives". Helus died later at Los Robles Regional Medical Center.
Nick Steinwender, student body president at nearby California Lutheran University, rushed to the scene when he heard about a shooting at the bar where he knew friends and fellow students were. "From what I heard, the gunman started shooting at the front desk. You know, I think it's going to be something that we're going to have to come together and move past".
Pepperdine University freshman Alaina Housley, 18, was at the bar with several friends for a night of line dancing. Well, I don't want to say he was dead, but he was shot.
"I'm just reeling, riding on adrenaline right now", he said. My son thought it was a joke, so I pulled him down and got some cover.
Bar patron describes what she saw when shooting broke out in Thousand Oaks.
"It was really, really, really shocking", she told KABC-TV.
This undated photo provided by the Ventura County Sheriff's Department shows Sheriff's Sgt Ron Helus, who was killed in the shooting.