A man was struck in the head with a pipe during an altercation in downtown Modesto on Tuesday afternoon, police reported.
Investigators said two men and a woman accosted the man and stole his bicycle, Sgt. Brian Findlen said.
As police responded to the incident, they spotted a pickup truck in the 700 block of 15th Street and ordered the driver to stop.
One man got out, and it turned out to be the man injured in the fight a few minutes before.
The driver refused to get out of the truck, Findlen said, so an officer fired a bean bag from a shotgun to break a window in the truck. The driver then surrendered.
The man injured in the fight was taken to a hospital but a short while later ran out of the building and disappeared.
Findlen said no one was arrested, and that officers are trying to find whoever assaulted the man and stole his bike.