The man arrested over the weekend after a series of crashes in Sonoma County that authorities attributed to road rage, one of them fatal, has now been charged with murder and hit-and-run, the district attorney confirms.Diego Alexis Diaz-Hernandez, 20, has been charged with vehicular homicide, assault with a deadly weapon, reckless driving, and hit-and-run, among other charges, following a Saturday afternoon rampage that began in Santa Rosa.The first collision that Diaz-Hernandez appears to have caused happened aroun 1 pm Saturday on Highway 12 near the intersection of Stony Point Road, in Santa Rosa. (Stony Point Road is a long, two-lane, north-south route that parallels Highway 101, connecting Santa Rosa with Cotati and the community of Stony Point to the south.)In that collision, as the Press Democrat reports, a Toyota Camry was run off the road and overturned, but no injuries were reported. Subsequently, just after 2 pm, Diaz-Hernandez was allegedly driving his Mazda SUV under the influence, south on Stony Point Road near a pumpkin patch in Rohnert Park, when he allegedly slammed into a Volkswagen Atlas SUV from behind multiple times. The Volkswagen was pushed into the oncoming lane where it was struck by an oncoming Mercedes SUV.A female passenger in the Volkswagen, 33-year-old Carena Piccinotti, was killed in the crash, and both a child and the driver the of the car were severely injured.Two people in the Mercedes were also seriously injured.A witness at the scene, roadside vendor Rosie Garcia, tells KTVU that it appeared the Mazda and the Volkswagen were racing along the road — though authorities believe the Mazda could have been chasing the Volkswagen.The Mazda fled the scene, and another crash occurred in Cotati, at a gas station near Highway 116 and Redwood Drive. In that crash, as Cotati Police Chief Chris Simmons tells KTVU, "We had a subject who had rear-ended an individual and then actually hit him again, so he hit our victim twice."A fourth crash occurred shortly therafter, at around 2:16 pm, on southbound 101, south of Pepper Road, and the Mazda allegedly rammed the other vehicle in that crash as well. In that collision, the Mazda became disabled, and CHP says that Diaz-Hernandez attempted to flee the scene on foot but was arrested."Through investigation, it was determined that the Mazda driver intentionally caused these crashes and also caused an earlier crash on SR-12 at Stony Point Road," CHP-Santa Rosa says in a release. "Officers determined the suspect was under the influence. The suspect was booked into Sonoma County Jail on multiple charges including Murder, Felony DUI, and Assault with a Deadly Weapon."Even though Officers Diaz-Hernandez has been charged, this remains an open investigation by multiple law enforcement agencies. Anyone with information on any of these incidents is asked to called CHP-Santa Rosa at 707-588-1400.Image via CHP-Santa Rosa