A mass shooting Wednesday night in the city of Thousand Oaks in Southern California, has left 13 people dead including an officer and a gunman, and at least 11 injured, local authorities said.
The gunman was identified as 28-year-old Ian David Long, a former Marine, said Ventura County Sheriff Geoff Dean.
Dean said his department had several contacts with Long over the years, including a call to his home in April when it was believed he may have been suffering from poor mental health.
"We believe he shot himself," Dean said.
Previously, Dean told the press that deputies responded to multiple reports of gunshots fired at Borderline Bar and Grill around 11:30 p.m. local time (0730 GMT, Thursday).
Deputy Sgt. Ron Helus went into the bar with another highway patrol officer. Helus was shot several times in confrontation with the shooter and died in hospital later, Dean said.
According to witnesses at the scene, the shooter threw a smoke grenade into the bar before opening fire with a handgun.
Madison Cummings, an eyewitness at the bar, told Xinhua that the shooter had a beard and short black hair, wore all black and held a black handgun.
"At the first sight, I thought it was a joke, because the music did not stop. But later I smelled the gun fire, then I knew it's real," she said.
"We immediately ducked down, freaking out," she said. As soon as the shooter was outside her eyesight, Cummings got up and went up to the door.
She sat in her car parked in front of the bar for 45 minutes until the cops walked the patrons to a safe place.
Helus was a 29-year veteran who was set to retire next year.
"Ron was a hardworking, dedicated sheriff's sergeant. He was totally committed, he gave his all and tonight, as I told his wife, he died a hero. He went in to save lives, to save other people," Dean said, choking up.
He said the motive of the shooter remains unknown.
The United States has one of the highest gun-related death tolls in the world due to lax gun control laws, according to a study released in August by the Institute for Health Metrics and Evaluation at the University of Washington.
On Oct. 27, a gunman opened fire inside a synagogue in Pittsburgh, Pennsylvania, killing at least 11 people and injuring six others. The gunman was charged with dozens of counts, including religious hate crimes.
