An 18-year-old boy was killed in a rollover accident on I-215 early Thursday. Now, investigators are trying to determine if the teen may have been racing another vehicle, if he and another driver were involved in horseplay or if it was a possible case of road rage.

Francisco Mendez, of West Jordan, was killed when his car rolled several times on the west-side belt near 1700 North, and then burst into flames. An autopsy was expected to determine whether Mendez was killed by the crash or the fire. When emergency crews arrived the vehicle was fully engulfed, said Utah Highway Patrol trooper Cameron Roden.

Witnesses told investigators that Mendez and another vehicle were "going back and forth at each other," Roden said. One car would move ahead of the other, and then other vehicle would catch up.

At one point, Mendez lost control of his vehicle, hit a concrete wall on the left shoulder, bumped off that and rolled off the right shoulder.

Speed was believed to be a factor in the accident, Roden said. Troopers hoped the autopsy and more interviews with Mendez's family might give them more information as to what he was doing that night and whether alcohol was a factor.

The search for the second vehicle involved continued Thursday.