PHOTOS: Mass shooting at nightclub in Thousand Oaks, California

At least a dozen people were killed after a gunman opened fire at a nightclub in Thousand Oaks, California.

Hundreds of people were inside the Borderline Bar & Grill when the gunfire rang out, authorities said. The suspect was found dead inside the nightclub.

The suspect was identified as Ian David Long. Among those who were killed is a Ventura County sheriff's sergeant, Ron Helus.

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