The shooting happened shortly before 5 p.m. near Ventura Avenue and Fraser Lane
The man who was killed has been identified as 21-year-old Devon Costa of Simi Valley.
It all started with a report of a man waving his hands and shouting in the street. A female deputy responded, and a struggle ensued. Investigators say the suspect started punching the deputy. Her dog then attacked the man, who allegedly continued to assault the deputy.
At one point, the deputy says the man went for her gun. That's when she shot him, sending him to the hospital. The man was pronounced dead a short time later.
The deputy sustained minor injuries during the incident.