PHILADELPHIA (CBS) -- The West Goshen Police Department has tweeted images of a truck they believe is connected to a shooting that killed a high school graduate moments before her car went off the road earlier this week.
Authorities in Chester County also released a sketch of the suspected driver of that vehicle.
It happened on Wednesday around 5:30 p.m. in the southbound lane of Rt 100 in West Goshen Township.
"A red pickup truck merged in at the same time and the man in the pickup truck pulls out a gun and shot her in the head killing her," said Chester County District Attorney Tom Hogan.
Police the Green Chevrolet Malibu being driven by 18-year-old Bianca Nikol Roberson went over the road and down an embankment after Roberson was shot in the head.
She was later found dead.
"Just turn yourself in!" cried Michelle Roberson, mother of the teen victim. "Please! You took my life, devastated this family, she was our life!"
Bianca's father Rodney Roberson said, "She was a good girl, just graduated from high school, loved by many, never bothered anybody. She was just a sweet girl, and I'm not just saying that because she's our daughter. I'm saying that because that's who she was. We want justice for our daughter. The person who did this, we want brought before the justice system."
According to Charles Gaza, with the Chester County District Attorney's Office, Roberson and the truck driver were both trying to get into a single lane when the incident occurred.
Police Chief Joseph Gleason said, "It was basically a cat and mouse game between these two vehicles."
Investigators say that the pickup truck was seen next to Roberson's car before the deadly encounter, it then sped off, entering Route 202, and continued to flee on the Paoli Pike.
On Friday, authorities released a sketch of the gunman.
"The suspect is a white male, medium build, age 30-40, with blond hair or light brown hair. So the police in three states are on the lookout for this suspect and will not stop until they find him," Hogan said.
Roberson had just graduated high school and was getting ready for her freshman year at Jacksonville University.
Crime Stoppers has offered up a $5,000 reward for information leading to an arrest.
Anyone with any information is asked to call police at 610-696-7400.
for more features.