A UPS truck driver was run over by his own rig while trying to attach a set of double trailers in San Antonio on Tuesday.

It happened on October 17th at approximately 5:15 a.m. at a UPS facility at 6400 Seven States.

According to local News 4 San Antonio, 59-year-old Terry Lee Sawyer was connecting a tractor to a set of double box trailers when he got out of the cab in order to apply the airbrakes on the second trailer.

The semi truck then began to roll backwards. Sawyer ran towards the cab to try to stop the rolling big rig, but got caught beneath the tires and was crushed, reported KSAT News.

Sawyer was killed in the accident.

Officials are still investigating the details of the incident.