One adult and one child were killed in a collision involving a concrete truck and a school bus in Bastrop County, Texas, on Friday.

The crash occurred shortly before 2 p.m. on Friday, March 22 as a Hays Consolidated Independent School District bus was returning from a field trip to a zoo.

The school bus, loaded with 44 preschool students and 11 adults, was westbound on State Highway 21 when it was struck head-on by an eastbound concrete truck.

Following this crash, the driver of a Dodge Charger collided with the rear of the school bus.

A male Pre-K student and the driver of the Dodge Charger were killed in the crash.

Four people were airlifted for treatment of critical injuries. Ten people were transported by ambulance with serious injuries.

It isn’t clear whether the concrete truck driver will be charged, KXAN reports.

The crash is under investigation by the Texas Department of Public Safety.

“There are no words that can express my sorrow for the student’s family, the Tom Green Elementary School family, and our greater Hays CISD community. I am also saddened to learn of the death of a person who was driving a car that was on the road behind our bus,” wrote Hays CISD Superintendent Eric Wright in an email to parents.