A new report by the Texas Department of Public Safety has released what investigators believe caused a five-vehicle crash that left five dead in Collin County.

The report states that 16-year-old Zoe Wilson was driving north on SH 121 in a Pontiac Grand Prix with her three friends -- 16-year-old Madison Kenney, 15-year-old Abigail Kendall and 15-year-old Brianna Gesino -- when Wilson began to slow down to turn left onto County Road 528.

Anne Spann was driving a Dodge Ram 1500 pickup truck behind them when DPS believes she "failed to control speed" and hit the back of the Pontiac.

Kendall and Gesino, who were sitting in the back seat, died upon impact. Wilson and Kenney were taken to the hospital.

Spann, 45, her husband Christopher, 42, and son Christopher Spann, Jr., 14, were taken to the hospital with non-life threatening injuries.

The report reveals that after the initial impact, the Pontiac was pushed into southbound traffic, hitting a Ford Focus. That vehicle "spun counter clockwise approximately 90 degrees" into the path of a Ford F-450 utility truck.

Julie Trimble, 51, and Wayne Trimble, 51, who were in the Focus, were both killed at the scene. Their daughter, 24-year-old Heather Trimble, died a few days later at the hospital after doctors delivered her unborn child. Her 4-year-old daughter was injured but survived.

The Ford truck driver, 62-year-old Billy Vanhoose, of Rowlett, sustained serious injuries and was taken by air ambulance to Medical Center Plano.

After the Pontiac hit the Focus, it was then pushed into a Subaru, which rolled into a ditch. The driver of that vehicle, 17-year-old Emrie Morris, was seriously injured and taken to the hospital.

DPS says the crash is still under investigation.