BIG SPRING, Texas — Authorities say the driver of a car was intoxicated when it was involved in a December crash that killed a person aboard a bus carrying West Texas high school cheerleaders.

A Texas Department of Public Safety report says 59-year-old Sandra Dunson was intoxicated due to drugs and alcohol. A DPS spokesman says Dunson died in March, when the case was still under investigation.

Dunson’s car was struck from behind by a semitrailer that then crossed the median and struck the small bus from the Iraan-Sheffield school district, killing cheer sponsor Elizabeth Pope.

The report says either Dunson made an unsafe lane change in front of the semitrailer or the semitrailer didn’t control its speed while traveling in the same lane as Dunson and struck her vehicle.