The limo burst into flames the night of May 4 as it crossed the San Mateo Bridge heading towards the Peninsula. The fire killed five women. Four others survived by crawling out of a narrow opening to the driver's compartment.
In June, ABC7 News reported that the CHP had determined the cause of the fire was a rupture of the air springs. Sources with knowledge of the probe told us that the air springs -- called balloons -- in the rear of the limo somehow deflated, setting off a domino effect that led to the fire.
Witnesses say the back of the Lincoln town car was extremely low to the ground while it was traveling across the bridge.
Yusef Mustafa owns Royal Auto Repair, a garage that services limousines. He explained the sequence of events to ABC7 News.
"These are the air springs; so in other words, they carry the weight of the car," Mustafa said. "So when one of them has a rupture on it, the whole car drops down, basically almost on the tires. So when the car drops down, these parts of the drive line usually it will be hitting on this part right here and that will create a friction and it winds up a lot of heat."
"The car would be jumping like a horse," Mustafa continued. "If there's a load in it, it would be bottoming at the ground, which is I think what happened. It bottomed on the ground and unfortunately, the gas tank is right there. The car with the weight, it bounced down too hard, and ended up hitting the gas tank, which is right at this spot here. It might have hit the gas tank and then you see, when it hits the ground it will create a spark. There's a spark here and there's fuel going down. So it catches fire."
Once the CHP discovered what caused the fire, the agency began its investigation to see if anyone was criminally negligent.
They focused on the driver, Orville Brown, and the owner of the limousine company, Kultar Singh. Sources tell ABC7 News, at the end of July, the CHP decided there was no evidence to press criminal charges against the two men.
But then, Brown's estranged wife Rachel Hernandez-Brown said publicly that the two argued on his cellphone shortly before the fire as he was driving.
"I'm sure he could have saved them, but he was too busy on the phone and I know he was videotaping," Hernandez-Brown said.
Hernandez-Brown charged that her husband was playing music too loudly and not paying attention.
When her media interviews surfaced, investigators renewed their probe of Brown to see if he was too distracted to react quickly to the emergency.
Sources tell ABC7News that CHP reviewed his cellphone records and determined that he had not been on the phone with his wife during the fire and that there was no other evidence to charge him criminally.
The CHP is expected to announce its findings that the fire was the result of a mechanical failure next week. The California Public Utilities Commission tells ABC7 News it is waiting for that report before it considers imposing a $7,500 fine on the limo owner. The CPUC permit for the limo allowed only eight passengers. The night of the fire it was carrying nine.