Ian David Long, 28, is believed to have been the gunman in Wednesday night’s shooting at the Borderline Bar & Grill in Thousand Oaks, California, Ventura County Sheriff Geoff Dean said.
Authorities found the gunman dead inside an office adjacent to the bar’s entryway, Dean said. “We believe he shot himself.”
The gunman used a Glock 21 .45-caliber handgun designed to hold 10 rounds plus one in the chamber, but the gun had an extended magazine, the sheriff said. Investigators didn’t immediately know how many rounds the magazine could hold, he said.
Long was a US Marine Corps veteran, Dean said.
“We have no idea what the motive was at this point.”
Deputies are at Long’s home, seeking to serve a search warrant, Dean said.
Investigators believe Long arrived Wednesday night at the bar in a car, shot a security guard who was standing outside and then stepped inside. It appears that Long then shot other security workers and employees inside and opened fire further inside the club, Dean said.
Law enforcement had several previous contacts with Long, including in April, when officers were called to a disturbance at his home, the sheriff said.
“He was somewhat irate, acting a little irrationally,” Dean said. Mental health specialists talked to him and didn’t feel he qualified to be detained under the state’s “5150” mental health detention law , Dean said.
Long also had been a victim of battery at a different Thousand Oaks bar in January 2015, the sheriff said.