THOUSAND OAKS, Calif. (AP) - A law enforcement official says the gunman who killed 12 people at a Southern California bar posted to social media during the attack.

  

The official told The Associated Press that Ian David Long had Facebook and Instagram accounts and that he posted about his mental state and whether people would believe he was sane.

  

Authorities haven't determined a motive. The official said investigators are looking at possibilities including whether the gunman believed his former girlfriend would be at the bar.

  

The official was briefed on the investigation into Wednesday's night shooting but wasn't authorized to discuss it publicly and spoke to the AP only on condition of anonymity.

  

Long shot and killed 12 people, including a police sergeant, at the Borderline Bar and Grill, a country music bar in suburban Los Angeles. Authorities believe he killed himself.