Dallas County sheriff's deputies spent Sunday morning investigating a deadly rollover crash on Stemmons Freeway, near Mockingbird Lane.
It happened at 4:30 a.m. in the southbound lanes of the highway.
The driver of a car lost control, left the roadway and hit several trees, deputies said.
One person was thrown from the vehicle and died at the scene. Another was taken to a local hospital with serious injuries, deputies said.