An 18-year-old who died in an apparent road rage incident was shot in the head before the vehicle crashed and a manhunt is on for a driver, authorities in Pennsylvania said Thursday.

Bianca Nikol Roberson and a man driving a red pickup truck were trying to merge in a lane simultaneously on Route 100 in Chester County on Wednesday evening when the incident turned deadly, the district attorney’s office said.

"And a man in the red pickup truck pulled out a gun, and shot her in the head, killing her," Chester County District Attorney Tom Hogan said.

Roberson’s car then veered off the road and crashed, WPVI-TV reported. Highway-camera footage revealed Roberson and the man in the pickup having some sort of incident before the crash.

Police said the pickup truck fled the scene and now authorities are searching for the driver.

“This is now a murder case,” Hogan said. “A young woman has died senselessly.”

Roberson had recently graduated West Chester High School and was heading to Jackson University in two weeks to begin freshman orientation, according to the station.

Her family is hoping the driver turn himself in.

“If you don't even think it was your fault, and have a conscience, come forward and give us some closure and explain in your own words what happened," Roberson’s father Rodney said.

Police said the driver was about 30 to 40 years old with a medium build and blond hair, adding that the make of truck was a Chevy. Police consider the man armed and dangerous.