It pretty clearly wasn't an accident.
With slightly different timing, or hitting, say, an oncoming car it sure would have looked like one.
We're not dealing with nice people here...
They observed the car fire before impact. They should be concerned about their well-being at this point in time and consider leaving the area for awhile.
Whoever did this is still loose (Middle Eastern terrorist, Dixie Mafia, etc.).
I think that it's obvious that Ms. Smith underestimated how dangerous the people she'd delt with were. This could be the work of a past client but so far Odtllah is the only client we know of (and he was still mediator in this transaction).
One of the men's lawyers suggested that Ms. Smith must have led a double life and that is what brought this about, not the current case she was about to testify on.