Authorities say 36-year-old Sonya Coronado died April 24 of injuries suffered two weeks after her SUV swerved off the road on Interstate 17 near the Sunset Point rest area.
Witnesses say they saw the driver of a pickup truck pull up alongside Coronado's vehicle, then make an obscene hand gesture before driving in front of her SUV.
They say the maneuver forced Coronado into the median where she lost control and her vehicle overturned numerous times.
Coronado joined the county Attorney's Office in 2000.
Yavapai Silent Witness is offering the reward for information leading to the arrest of the driver involved.
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