PARKER, Colo. — The Colorado State Patrol is still trying to determine why a car rolled over and caught fire southeast of Denver, killing five people early Sunday.

Trooper Tim Sutherland said no other vehicles were involved in the accident when the car went off the road and rolled several times.

The state patrol sent out a tweet calling it a “horrible” accident. Authorities could not immediately say if the accident involved adults or children, and whether they were male or female.

He said investigators had a hard time determining the make of the vehicle because the fire was “devastating.”

“It looks like excessive speed was a factor,” he said.

The accident happened about 6 a.m., east of Parker, which is about 25 miles southeast of Denver.

The highway was closed for seven hours while the investigation was conducted.