Lindsey Combs, 32, was killed in her driveway Monday in Martinez, Ca. after a load of gravel in a truck's trailer tipped over and fell on top of her car while she was inside. Her four-year-old daughter reportedly watched as the gravel crushed her mother, who was two months pregnant.

According to the San Francisco Chronicle, construction workers apparently asked Combs Monday afternoon to move her car farther up her driveway so they could continue their work constructing a half-mile stretch of sidewalk. As she tried move her car, the gravel trailer tipped over.

"Someone knocked on her door, the lady came out, then actually the chain of events that happened from there are under investigation as to how the gravel load came down onto the woman's car, pinning her and killing her inside," Julia Bernstein, a spokeswoman for California's Occupational Safety and Health Division, told Reuters. "It was not expected, and it was absolutely an accident."

Combs' neighbor, Travis Hegarthy, heard the trailer crash, telling the San Jose Mercury News, "It sounded like two cars going 80 mph going head on into each other. I didn't expect to see a dump truck on top of a car":

Hegarthy said he joined several construction workers trying to get the woman out of the car, but the sheer weight of the truck made it impossible. One worker jumped into a backhoe to try to drag the truck off, but even that machine couldn't do it, he said.

According to the Chronicle, the truck belonged to a private company—JJR Construction of San Mateo—contracted by the city of Martinez; the agency has six months to complete an investigation into the incident.

Image via CBS San Francisco. Contact the author at aleksander@gawker.com .