The family of a Pennsylvania high school graduate is heartbroken after she was shot and killed by an older man during a road rage incident, said police.  

Bianca Nikol Roberson, 18, of West Chester, Pennsylvania, was driving a green Chevrolet on Route 100 on Wednesday evening. Roberson attempted to merge into a lane that a red pickup truck was also trying to merge into at the same time.  

"Route 100 South drops down from two lanes to one lane where it merges into Route 202," Chester County District Attorney Tom Hogan said during a press conference Thursday night. "At that point her car started jostling with a red pickup truck. Not actually hitting but both of them trying to merge together."

In a fit of road rage, the driver of the red pickup truck pulled out a gun and shot Roberson in the head, instantly killing her. Roberson's car went off the side of the road and crashed into a wooded area. The driver of the pickup truck fled the scene by driving down the shoulder of the road. 

"This is now a murder case," Hogan told NBC Philadelphia. "A young woman has died senselessly."

The driver of the pickup truck is described as a medium-built, white male, 30 to 40 years old with blond or light-colored brown hair. His vehicle is described as a small, red Chevrolet pickup truck with faded paint.

"Every cop in three states is looking for this red pickup truck and looking for this defendant," Hogan said. "At this point, we're asking anybody who saw anything on Route 100 going into Route 202 to call the West Goshen Police Department right now, tonight. Give us every bit of information you can."

"Turn yourself in, now," Hogan said. "Every second you are out there, you are only making this worse for yourself and worse for this young lady's family."

Roberson had just graduated this year from Rustin High School and was headed to Jacksonville University in the fall.

"A young lady in the prime of her life getting ready to go off to college," West Goshen Police Chief Joseph Gleason said. "Now the family has to consider burying her."

Roberson's father, Rodney Roberson, tearfully told NBC10 about his daughter's college aspirations.

"We were all excited for her," he said. "She was excited. We were just happy for her."