On Tuesday, a murder charge was filed against the suspect in the case.
The man believed to me responsible for the car crash is 68-year-old Nhan Van Nguyen, and authorities say he was under the influence of alcohol when he crashed that car.
Prosecutors say 31-year-old Jessica Avila Munoz was driving that car and on her way to pick up her 13-year-old daughter from school, when Nguyen ran a red light and slammed into her. Munoz later died at the hospital.
Now, the focus is on Nguyen who police say has four prior misdemeanor DUIs. Here's legal analyst Steven Clark.
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"What the DA is saying is that this man was warned several times during his prior DUIs that if he got behind the wheel and killed somebody when he was under the influence, he could be charged with murder, and that day has now come."
Munoz had started working as a Sonoma County juvenile correctional counselor last year. Her co-workers, shocked and saddened over the news of her death.
"When I got the call from the Santa Rosa Police Chief, it took my breath away," said Sonoma County Chief Probation Officer Vanessa Fuchs.
"She loved her daughter more than anything and was her number one priority, and I myself and I know our department will do anything that we can to assist her with anything she needs," said Trevor Vannetti who is a juvenile correctional counselor who worked with Munoz.
We spoke with Damian Evans, the head of the Sonoma County Law Enforcement Association last Sunday. He was the one to swear Munoz in when she began working for the county last year. He reacted to Nguyen's extensive criminal history.
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"When we talk about the suspect and the four prior DUIs, it is something that brings a lot of concern especially in the law enforcement community - at some point you just have to shake your head," said Evans.
In addition to the murder charge, the 68-year-old Nguyen also faces a felony gross vehicle manslaughter charge, a felony DUI charge, and a charge of driving without a valid license.
"It's likely that this man if he's convicted of second degree murder, will not get out of prison, it carries a 15 to life term," says Clark.
Nguyen's last DUI was in 2016 - court records show he did less than a year of jail time. Clark says it's likely any past requirement of alcohol testing or other sanction had long lapsed.
Two fundraisers have been started to help Munoz's daughter and parents. The first which is organized by the Sonoma County Probation Peace Officers and can be found at here.
A friend of Jessica's has organized a GoFundMe for the family that can be found here.