A teenage swimmer was swept away at a Jersey Shore beach, sparking a desperate four-hour search by police and lifeguards Sunday afternoon.

Josiah Jeremiah Robison, 15, was still missing Sunday night after he and a teen girl struggled in the waters off Brighton Ave. Beach in Spring Lake at about 2:45 p.m., police said.

A bystander reached the teenage girl, and lifeguards helped get her back to shore. But Josiah couldn’t be found.

Cops from police agencies along the shore joined the state police, the Coast Guard and the Monmouth County Sheriff’s office to search the waters.