ANTIOCH (CBS SF) — Divers will try to find a motorcycle rider on Monday who plunged off the Antioch bridge after colliding with a car Sunday afternoon.

Witnesses saw the motorcyclist fall into the water at about 4:30 p.m. Shortly after, the California Highway Patrol received a report of a collision on the bridge and shutdown the southbound side of the bridge.

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“Eyewitnesses from the accident scene said they saw a body hit the water,” Contra Costa County Fire Battalion Chief Eddie Gonzales said. “And they were in contact with some boats that apparently saw the body hit the water in a splash. And immediately boats went into the area and looked for them.”

Medical crews arrived on scene and found the motorcycle but no driver.

After two hours of searching, emergency personnel were not able to locate the body, Contra Costa County Fire Marshal Robert Marshall said.

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“They found some of his gear, they think,” Marshall said. “There’s no way to tie it to the rider himself, but they did find some belongings.”

Marshall said the setting sun was a crucial factor in calling off the search.

The motorcyclist was traveling south when the driver collided with a car and then “flew” over the west side of the bridge, Marshall said.

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The involved car remained on scene and Marshall said no one inside was injured.