HARTSVILLE, S.C. -- Authorities say two people trying to speed away from a Darlington County sheriff's deputy have died after their car struck a bridge and flipped and was then hit by the pursuing cruiser.

Sheriff Wayne Byrd said his deputy clocked a car doing 77 mph in a 45 mph zone around 2:30 a.m. Wednesday near Hartsville, but lost sight of it as he turned to pursue.

Byrd says Deputy Richie Stevens rounded a curve and found the car flipped on its roof after hitting a bridge. Stevens could not stop and hit the car.

Investigators say both people in the car died. Their names have not been released. The deputy and a volunteer riding along were treated and released from the hospital.

State troopers are investigating.