Huntington Beach police confirmed that an officer-involved shooting occurred around 4:30 p.m. at Warner Avenue and Hoskins Lane.
"The handgun was later determined to be a replica. The officer fired, killing the suspect," said Huntington Beach Police Lt. Mitchell O'Brien.
Witnesses say the incident began behind a restaurant where a man and a woman believed to be the man's girlfriend were arguing.
A police helicopter soon flew overhead after authorities were called in, as the man and woman headed toward a residential neighborhood.
Police wouldn't say if the man was pointing the fake weapon at officers.
"I think they should have done a little bit more investigation to see if it was a real gun because that's a pretty big mistake," said witness Derek Zeek.
Officers have not yet released the suspect's name.
The Orange County Sheriff's Department will now launch its own investigation into this shooting.
