THOUSAND OAKS, California - One of the 12 people killed in the mass shooting at a bar in southern California has ties Oklahoma.

Ventura County Sergeant Ron Helus graduated from the University of Oklahoma. Investigators said Helus was the first to exchange fire with the suspect, Ian Long.

According to his LinkedIn profile, Helus earned a master's degree from the University of Oklahoma in 2014.

So far, the university has not released an official statement but said it is "a tough time for the whole OU community today."

"When sergeant Helus and the highway patrol officer went in they immediately exchanged gunfire with the suspect. And that's when sergeant Helus was shot several times," said Ventura County Sheriff Geoff Dean.

The sergeant's colleagues escorted his body to the medical examiner's office Thursday afternoon. He had planned to retire soon after 29 years as a deputy.

Police said the suspected gunman was a marine corps veteran. They believe he killed himself.

Investigators said right now, they don't know the motive for the shooting.