The victim, a 19-year-old woman, was sitting in the passenger seat of a car that was parked in the 14400 of Valley Blvd.
A man approached the vehicle, struck the woman through an open window and took her cell phone, said Fontana police Sgt. Robert Morris.
The driver in the car hit the gas to flee the robber, but ended up striking a parked car. The robber then opened the door, grabbed the victim's purse and dumped the contents onto the floor of the vehicle before leaving.
He jumped into an older-model Honda del Sol with silver rims, police said. The robber is black, 18 to 20-years-old, 5-feet-8 inches tall and has dreadlocks. He wore a red jacket and khaki pants.
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