FULLERTON (CBSLA) — Officers trying to break up a fight between two men in Fullerton were forced to open fire on one man who charged at them with a knife.

The officer-involved shooting happened at about 9:30 p.m. Sunday in the area of Lillie and Commonwealth avenues. Police say the officers was on his way to another call when they were flagged down to help break up a fight between two men — one armed with a broomstick, the other with a knife.

While the man with the broomstick was being detained, police say the man with the knife charged at officers. The officers first deployed a less-than-lethal round at him, but it had no effect, so they were forced to open fire with their service weapons.

The man was pronounced dead at a hospital.

The investigation continued at the scene eight hours later. Drivers were advised to avoid the area.