Somebody had access to the car just before she drove away that night. Hidden in the back seat or trunk was an incendiary device with a fuel source of gasoline and probably a chemical starter such as acid and a dry chemical reactant. The chemical cocktail was a fused device based upon the time for the acid to eat through a container and ignite the accelerant which exploded the gasoline. It was designed to look like an accident while the car was in motion and with no way for the driver to escape. It would not appear to be a bomb and without witnesses at night the car would have burnt up with no physical evidence remaining.
This was professional and a hit on a witness to keep her quite.
By whom??????
This was not a simple case of Arkanside and someone definitely wanted this person to stop from telling more. Did she attempt to go for more money from someone she now was black mailing for help out of this mess?
Time to go over her records and life with a vacume cleaner and suck all the leads out before they grow cold. Smaller details have saved many lives and have helped arrest very bad people.
That is the best explanation I have seen so far and I think it will be the closest to the truth, that is if we ever learn the truth.