HALF MOON BAY (CBS SF) — One person was dead and another believed to be missing after an unoccupied boat was spotted rapidly spinning in circles in the Pacific Ocean off Half Moon Bay, authorities said.

The Coast Guard said a body — identified by the coroner as 74-year-old Fremont resident Dung Duc Nguyen — had been found in the water. A search had been launched for a second person — identified as Tuan “Tom” Tran — who was also believed to be aboard the Boston Whaler.

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Pillar Point Harbor personnel contacted Coast Guard Sector San Francisco around 1 p.m., Sunday, reporting the vessel Tran was operating was found approximately eight miles south of Pillar Point Harbor.

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A Pillar Point Harbor member found one boater unresponsive near the adrift vessel.

A 47-foot Motor Lifeboat crew from Coast Guard Station Golden Gate, an MH-65 Dolphin helicopter crew from Coast Guard Air Station San Francisco and Coast Guard Cutters Barracuda and Hawksbill searched for the second boater Sunday afternoon and evening. The Hawksbill was scheduled to continue searching throughout the night.

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Anyone with information regarding Tran’s whereabouts should contact Coast Guard Sector San Francisco watchstanders at (415) 399-3451.