Sgt. Ron Helus, the sheriff’s deputy who died in a mass shooting in Thousand Oaks, Calif., was killed by a highway patrolman's gunshot, authorities said.

Details about the 12 people killed after a gunman entered a California bar and opened fire Wednesday night are beginning to emerge.

Sgt. Ron Helus, the sheriff's officer killed in the Borderline nightclub mass shooting in Thousand Oaks, Calif., was a husband, father and veteran officer on the verge of retirement.