A 28-year-old Marine veteran killed 12 people when he opened fire inside a busy bar in Thousand Oaks, California. Here's how the attack unfolded:
A 28-year-old Marine Corps veteran killed 12 people when he opened fire inside a busy bar in Thousand Oaks, California on Wednesday before killing himself and sending at least 15 others to the hospital with injuries.
The mass tragedy, which claimed police officer Sgt. Ron Helus and at least one survivor of the Las Vegas massacre among its victims, is the latest in 307 mass shootings that have occurred in the US so far in 2018.
No motive has been released by investigators.
Here's how the attack unfolded:
The western-themed bar was reportedly popular among students from nearby universities including California Lutheran University, California State University Channel Islands, Pepperdine University, and Moorpark College.
Long was reportedly dressed in all black and carrying a Glock 21 .45-caliber handgun as he approached the building.
After shooting a security guard outside, Long stepped inside to shoot several employees and opened fire inside the busy bar, shooting into a crowd of about 40 people on the dance floor.
Patrons reportedly hid under pool tables and used furniture to break windows and escape outside, some jumping from the second story.
Video footage showed police officers standing outside the bar for up to an hour after their initial arrival. Other footage showed civilians carrying out injured people from the bar and tending to them.
Officers from the FBI Joint Terrorism Task Force and the Bureau of Alcohol, Tobacco, Firearms and Explosives were present at the scene.
The gunman had been "down with a gunshot wound" when officers entered the building, Ventura County Sheriff Geoff Dean said, adding that there was "blood everywhere."
A witness told KABC-TV the gunman reloaded the gun at least once and Long fired at police officers when they entered the building, killing a deputy sheriff later identified as Sgt. Ron Helus.
Long was eventually found dead of a self-inflicted gunshot wound inside the bar's office.
At least one of the survivors from the Route 91 Harvest Festival massacre was shot Wednesday night.
Gunman Stephen Paddock killed 58 people when he opened fire from his 32nd-floor hotel room on the crowd below in Vegas.
Out of more than 100 people who had been in the Borderline Bar & Grill, a witness estimated that dozens had survived the shooting in Las Vegas, though that was unconfirmed by authorities.
Multiple reports began to reveal the victims' identities. CNN reported the known names so far of those confirmed dead included:
Approximately 2,000 people attended a vigil for the shooting's victims led by Thousand Oaks Mayor Rob McCoy.