MADEIRA BEACH, Fla. (WFLA) — The search for a missing swimmer will enter its second full day Friday in John’s Pass after four swimmers were swept out to sea but only three returned.

The first calls for help came in at 6:45 p.m. Wednesday as good Samaritans helped rescue three swimmers, but the fourth was unaccounted for. The Pinellas County Sheriff’s Office is leading the search, along with the U.S. Coast Guard and other agencies. The search includes a dive team and sonar technology.

“You see a bunch of boats parked up there and you can see the currents sucking them through the bridge back out into the gulf,” Andrew Farid, a tourist who witnessed the search in progress, said.

The area known as John’s Pass is widely known to have strong rip currents. The area has signs indicating no swimming is allowed in the area.

“Out in the water there’s been probably two police boats like they’re searching for something,” said another man who told 8 On Your Side he had been observing search efforts.

The missing swimmer has only been identified as an adult male, but no other details were given by officials when the search was first reported.