Deputies weren't hurt during Thursday's confrontations with the suspect in an unincorporated area near Whittier.
The man's name hasn't been released.
A Sheriff's Department news release says the man was confronted twice by deputies.
A deputy responding to a man-with-a-gun call saw the suspect, who and refused to comply with deputy commands and reached into his waistband.
Fearing for his life, investigators say the deputy fired his weapon at the man. It's unclear if he was wounded.
The suspect ran away and a short time later he was confronted by deputies.
The man was wielding a large knife and charged deputies when he was shot to death.
The knife was recovered. It's not known if he had a gun.