Conner said an autopsy performed Monday in Allentown, Pa., determined cause of death as blunt force trauma to the chest, abdomen and pelvis.
A brother and sister that were in the same car as Thomas were flown to Hershey Medical Center, according to state police. April Shipley, 16, of Chambersburg, was in critical condition in the critical care unit. A hospital spokeswoman said Scott Shipley, 18, of Shippensburg, was in serious condition.
The driver of the car they were in, Dennis E. Varner, 22, of Shippensburg, was in fair condition at Chambersburg Hospital Monday, according to a hospital spokeswoman. The driver of the other car, Emily Ann Estep, 16, of Chambersburg, was in satisfactory condition, the spokeswoman said.
A state police expert in reconstructing accidents was called in from Harrisburg to investigate the accident, which closed down that section of Philadelphia Avenue for more than five hours. Barracks Commander Lt. Thomas Barkdoll said crash experts are often called in for major accidents to resolve questions about possible prosecution or civil liability.
The report said the accident was still under investigation and police were consulting with the Franklin County District Attorney's Office.
The report said Varner was the driver of a Dodge Omni that was on the shoulder of the northbound lane facing south. Varner was trying to turn the car around and drive north when the rear quarter panel of the driver's side was hit by a northbound Eagle Summit driven by Estep, according to the report.
The impact caused the Omni to spin around twice before coming to rest facing south in the northbound lane, the report said. Varner and one of the other passengers in the car were thrown out, the report said.
Thomas was still in the car when Preston Strayer, an off-duty Chambersburg police officer who lives nearby, pulled her from the car and tried unsuccessfully to revive her, according to Jason Strite, a volunteer firefighter who was at the scene.
No one in either car was wearing a seat belt, police said.
Estep had to be freed from the wreckage of her car by ambulance personnel, the police report said. She suffered injuries to her hand, according to the report.