A rowdy incident during a "zombie walk" outside the Comic-Con convention in San Diego on Saturday left a 64-year-old woman with "serious arm injuries," police said.
The walk, a high point of the annual convention, involves conventioneers in frightening costumes and with painted faces walking on the streets near the city's convention center.
The incident began around 5:30 p.m. when a "deaf family with small children" was in a car at an intersection waiting for the marchers to pass by, police said.
After waiting several minutes, the 48-year-old driver drove slowly forward because the children in the car were afraid of the marchers, police said.
Several of the zombie marchers surrounded the car and began pounding on it. Some jumped on the vehicle, and the windshield was shattered, police said.
"The family was scared so the father drove forward again trying to get away from the angry crowd," Officer David Stafford said.
The 64-year-old woman was then struck by the car and fell underneath the vehicle, police said. Members of the crowd chased the car as it moved forward until the driver spotted a police officer and stopped.
The woman was taken to a hospital, and the incident is under investigation, police said.
Organizers of the "zombie walk" said the injured woman was not part of the march. "Our thoughts are with her," organizers said on the group's twitter page.