At least 14 people were dead and another 17 injured in a shooting Wednesday in San Bernardino, California, when gunmen who were heavily armed and “on a mission” opened fire during a function at a center for people with developmental disabilities, police said.

Police believe two alleged shooters — a county employee and a woman with whom he was in a relationship opened fire around 11 a.m. at the Inland Regional Center. They were armed with assault weapons and “prepared to do what they did as if they were on a mission,” San Bernardino Police Chief Jarrod Burguan said.

Investigators were still trying to determine a motive, but have not ruled out terrorism.

“We have no information at this point to indicate that this is terrorist related in the traditional sense that people may be thinking. Obviously at minimum we have a domestic terrorist type situation that occurred here,” Burguan said. The FBI later said that terrorism was a “possibility.”

Read the article “2 San Bernardino Shooting Suspects Identified After Being Killed in Shootout, Police Say” on abcnews.go.com.