The shooting was reported near the Temecula Courthouse, in the intersection of County Center Drive and Ynez Road, at about 10:30 a.m., officials said.
Witnesses said the shooting followed what appeared to be a domestic dispute between the man and a woman arguing in the parking lot of the county's administrative building.
Ivan Garcia said yelling was coming from a Jeep in the parking lot next door to where he was. He said he noticed a man being verbally abusive toward a woman.
"He's just going berserk - hitting the steering wheel, socking everything," Garcia said. "I could see the guy just kicking the door and throwing crap and just yelling at her."
The man tossed boxes of household goods, clothing and other items onto the ground of the parking lot. Garcia said he watched the man's behavior become more violent and he became concerned for the woman's safety.
"I thought he was going to hit her, so I'm sitting there with my phone. He looks over at me and is like, 'What the F are you doing? Put your phone away,'" Garcia said.
Garcia said he went inside to tell coworkers, while outside a deputy had just arrived. Another witness said that is when the irate man grabbed an object from the pile of boxes and lunged at the deputy.
This led to a scuffle, and the deputy-involved shooting occurred. The man was pronounced dead at the scene. Crime scene tape closed off the roadway in the surrounding area. The shooting also left witnesses and those in the community shaken and concerned for the deputy's well-being.
"We just saw one of the police officers was hurt, bleeding from his head. But we think he might have just fell back. There was a scuffle," Garcia said.
Riverside County sheriff's officials confirmed in a tweet no deputies were injured in the shooting.
Attn media: we can confirm an Officer involved shootn occurred in Temecula.. OFFICER WAS NOT SHOT .... further info 2 follow— Media Info Bureau (@RSOmedia) November 15, 2016
The investigation was ongoing.