Officers were called to a clothing manufacturer on the 1400 block of East Valencia Drive Wednesday night after reports came in about an employee assaulting his boss.
When police arrived the suspect was gone. However, he returned a short time later wielding a handgun.
Police say the officer feared for his safety and the safety of others at the scene, so he opened fire, killing the suspect.
The suspect's handgun was recovered at the scene.
The Orange County District Attorney's Office is investigating the shooting.