KNIGHTSEN, Calif. -- A device thought to be dynamite evacuated over 200 homes for over four hours Wednesday in the unincorporated Contra Costa County township of Knightsen.

Police Wednesday night called the suspected bomb "a fake."

Residents living around a motor home at 60 Broadway were allowed back into their homes at 6 p.m., about 50 minutes after a police bomb squad detonated the device, said Contra Costa County Sheriff's spokesman Jimmy Lee.

After inspection, it was determined that what had appeared to be a bundle of dynamite attached to a timer and antenna wrapped with duct tape was nothing more than a handful of road flares.

The device was reported to police at 1:30 p.m. A police bomb squad was dispatched to the motor home and residents within a one-mile radius of the scene were evacuated and directed to a middle school on Frank Hengel Way near East Cypress Road.

Lee said authorities are searching for anyone responsible for planting the device. Crime scene investigators from the Contra Costa sheriff's office went over the RV where the device was found and detonated looking for evidence to learn more about the dangerous hoax

Walnut Creek is the only city in Contra Costa County that has a bomb team at its disposal, Mark Covington of Walnut Creek police said. The team was sent out after receiving a request from the sheriff's department, which is managing the incident.