Last night a limousine carrying nine women on their way to a bachelorette party burst into flames on the San Mateo Bridge, killing five women inside—including the bride.

The fire started around 10 p.m. in the westbound lanes of the bridge that is about 20 miles southeast of San Francisco and connects San Mateo and Alameda counties on either side of the Bay. The driver pulled over, and he and four women in the bachelorette party were able to escape the fire. Some Good Samaritans pulled over, but the fire moved quickly and they weren't able to rescue the five other women trapped inside in time, according to ABC 7.

The limo wasn't involved in any sort of accident or collision beforehand, and investigators are trying to figure out what caused the fire.

"Looking at the photos, it appears it started in the trunk," California Highway Patrol spokesman Ron Simmons told CNN. "But at this time, we don't know officially if the fire started inside the vehicle or on the exterior."

A passer-by tweeted a photo of the limo just after it burst into flames:

The limo had just picked up the women in Oakland, and it planned to take them to the Crowne Plaza Hotel in Foster City for the bachelorette party, according to the San Jose Mercury News.

The survivors were treated at nearby hospitals for burns and smoke inhalation. The women in the party were all in their 30s and 40s. The CHP released the names of the surviving passengers and the driver, but is still waiting to notify next-of-kin to release the names of the deceased. The fire's survivors include Mary Grace Guardiano, 42, of Alameda; Nelia Rafael Arellano, 36, of Oakland; Amalia P. Loyola, 48, of San Leandro; Jasmine Desguia, 34, of San Jose. The driver is Orville F. Brown, 46, of San Jose from Limo Stop, Inc.

The company that runs the limo service Limo Stop said the company is cooperating with the California Highway Patrol's investigation. Limo Stop dispatcher Pam Kaur told the Mercury News, "We are very shocked. We are cooperating with the police."

The westbound lanes of the bridge were closed while officers investigated the fire, but they were reopened Sunday morning.

The Oakland Tribune has more photos and CNN has video from the aftermath: