The victim, a 32-year-old mentally disabled man, was outside his home at 3838 Clayton Road at about 6 p.m. when a group of six to seven teens on bicycles rode up to him and began teasing him, Hughes said.
The harassment escalated and the teens allegedly began throwing rocks at the victim and hitting him with sticks, Hughes said.
The victim's family intervened and the teens ran off.
The man had one minor injury but did not require emergency medical treatment.
Officers searched the area but didn't find the boys, who were described only as black males on bicycles ranging in age from 14 to 17 years old.
Detectives are still investigating the case and are trying to determine whether the teens attacked the victim because of his disability, Hughes said.
Anyone with information about the incident is asked to call Special Victims Unit Sgt. Tiffany Leftwich at (925) 603-5959. People who wish to remain anonymous can call the Police Department's tip line at (925) 603-5836.