Thousand Oaks shooting gunman identified as 29-year-old male who legally purchased gun that killed a dozen people, including a police officer

The gunman in a fatal mass shooting at a Thousand Oaks bar and music venue has been identified as David Ian Long.

According to ABC 6 Action News, Long, 29, went by his middle name and legally purchased the .45-caliber handgun used in the mass shooting.

Long was reportedly found dead at the scene, and 12 other people were killed, including Ventura County Sheriff Sgt. Ron Helus, a 29-year veteran of the force who is believed to have been the first or among the first on the scene.

The names of the additional victims have not yet been released, and authorities have not yet determined a motive for the fatal gun massacre.

CrimeOnline will provide further updates when more information is available.