The gunman suspected of killing at least 12 people at a Southern California bar late Wednesday evening has been identified as David Ian Long, according to reports.

ABC reporter Mike Levine reports that Long used his middle name “Ian,” according to neighbors. The earliest reports of his identity merely called him “Ian Long.” Law enforcement officers say Long was a veteran previously in the U.S. Marine Corps.

Police revealed they previously had multiple contacts with Long in the past several years for minor offenses.

In 2015, he was a victim of assault and battery during a bar altercation. Law enforcement officials say officers were called to Long’s resident in April, where he was described as “somewhat irate, acting a little irrationally.”

Long was cleared after an interview with the Crisis Intervention Team and mental health specialists.

NEW: Ventura County Sheriff: Deputies were called to suspect's house earlier this year, found him "irate, acting a little irrationally." Mental health specialist met with him. Deputies have secured his residence, seeking search warrant. https://t.co/YMTCrOEG5j pic.twitter.com/KqjbGUeYPZ — ABC News (@ABC) November 8, 2018

KTLA shared a photo of Long to social media.

#BREAKING: Photo of Thousand Oaks shooting suspect Ian David Long, a Marine veteran https://t.co/7EHNjj027E pic.twitter.com/SM5aNguZ3v — KTLA (@KTLA) November 8, 2018

Using a smoke bomb and a handgun, a hooded gunman dressed all in black opened fire during “college night” at Borderline Bar & Grill, a popular country bar in Thousand Oaks. The gunman was later found deceased.

Authorities said the motive for the attack Wednesday night was under investigation.

Patrons screamed in fear, shouted “Get down!” and used barstools to smash second-floor windows and jump to safety as gunfire erupted at the hangout for college students. The dead included people inside the bar and a sheriff’s sergeant who was the first officer inside the door, Ventura County Sheriff Geoff Dean said.

“It’s a horrific scene in there,” Dean said in the parking lot. “There’s blood everywhere.”

Earlier, a law enforcement official said that authorities had identified the gunman. The official said the 29-year-old man deployed a smoke device and used a .45-caliber handgun. The official was not authorized to discuss the investigation publicly and spoke on condition of anonymity.