As California Highway Patrol investigators continue to examine the charred vehicle, multiple sources told Eyewitness News' sister station KGO-TV exclusively that the air springs in the rear of the limo ruptured, triggering a domino effect that led to the fire.
Four women were able to escape, but five others died. The group of nurses was celebrating a recent wedding. The new bride was among the dead.
According to KGO-TV, witnesses said the back of the Lincoln towncar was very low to the ground while it was moving across the San Mateo Bridge on the night of May 4. There were nine women on board, which is one more than the limo's permit allows.
Yusef Mustafa, who owns a garage that services limousines, told KGO-TV that the air springs basically carry the weight of the car.
"So when one of them has a rupture on it, the whole car drops down, basically on the tires," Mustafa explained. He said when the weight drops to the tires, it works up a significant amount of friction and heat.
According to Mustafa, the combination of that friction against the gas tank could have sparked the flames.
The investigation into the fire continues. Now that the cause of the fire is known, CHP investigators and the San Mateo County District Attorney's Office will have to determine whether there was any criminal negligence in the limo's maintenance.
KGO-TV and ABC News contributed to this report.