Marine police were set last night to give up the search for eight Vietnamese boat people reported missing at sea as doubts emerged about the report. A 27-year-old Vietnamese man, who raised the alarm on Monday morning, claimed he and eight others had to swim for it when their small boat sunk in high seas during Typhoon Sally on Sunday night. He claimed he survived after finding a sampan and clinging to it. But police, who came to his aid off Cheung Chau, said the sampan had been reported stolen from Peng Chau the previous day. He is being detained in Cheung Chau for further questioning. The fact that the boat had been reported stolen 24 hours earlier cast some doubt on his story, a source said. But the report was still being taken seriously and two marine police launches spent a second day yesterday scouring the waters for survivors. The man had claimed he, five other men and three women had been on a seven-metre boat when it sank 10 nautical miles south of Shek Kwu Chau. He said they had left Haiphong in Vietnam on August 20 for Japan. A spokesman for the Marine Rescue Co-ordination Centre said: 'If nothing is found, we will consider suspending the search.'