[Grammy]

"But how did perps set her on fire and get away immediately? Remote control incidiary device?"
How about driving up next to her and shooting some incendiary device into the car while she is driving? If she, or the car, is on fire, she will of course run off the road, trying to put it out. That would also explain the smoke inhalation.

[Martin Tell]

Shooting such a device would leave traces such as a broken window, cannister in the car, etc. And pardon my ignorence of the incident, but weren't the doors locked and windows rolled up?