California Highway Patrol inspectors have spent the past month looking into what caused a limousine to burst into flames on the San Mateo Bridge, leaving five members of a bridal party dead. Although CHP has yet to release an official report, ABC7 reports multiple sources have explained the problem began with a ruptured air spring that caused the rear of the vehicle to sag, building up heat and eventually sparking a fire near the gas tank.

As Yusef Mustafa, owner of a peninsula garage that services limos told ABC7's Vic Lee, the air springs carry the weight of the car on a rubber ballast. If a spring has ruptured, the whole car will sag "almost down to the tires." When the car rides that low, Mustafa told the station, parts of the drive line can rub against bottom of the car and create heat and friction. It's also possible that the limo's rear end bottomed out on a bump, which could have ruptured the gas tank and caused a spark. Eyewitnesses driving by the scene last month also claimed the limo's rear end appeared to be low to the ground and the fire appeared to have started in the trunk.

CHP's official investigation is still ongoing. Although they believe they have the cause of the fire, the next step is to determine whether Limo Stop Inc. was responsible for any criminal negligence with regards to the limo's maintenance. The limo was carrying nine passengers at the time of the incident — one more than the eight it was permitted to carry.

One survivor, who escaped through the partition to the front of the vehicle, previously claimed the driver did nothing to help the women trapped in the back. The driver also told his side of the story, claiming he initially thought the women were asking to smoke and he did what he could to pull the women out through the partition.

Previously: All San Mateo Limo Fire coverage on SFist