Updated

Five people reported to have been missing from a tour boat that sank in a storm off the southern resort island of Phuket are alive, Thai authorities said Monday, though it's unclear if the five survived the sinking or never got on the boat.

Phuket Gov. Norrapat Plodthong said authorities are trying to verify their details and some of them may have left Thailand.

Norrapat said the development came after new information emerged from Thai immigration and the Chinese Embassy.

The new information also showed there were 89 tourists, 87 of them Chinese, on the boat, instead of the previous figure of 93, he said.

The number of people who are missing has been lowered from 14 to 10, including the five who are alive but whose whereabouts are unclear, he said. The death toll remains at 42, including a body still trapped under the wreckage.

The double-decker Phoenix capsized and sank late Thursday afternoon after it was hit by 5-meter (16-foot) waves in one of Thailand's worse tourism-related disasters since the 2004 Indian Ocean tsunami that killed thousands.

Officials said all of the dead were Chinese comprising 13 children, 18 women and 10 men. The age and sex of the body still under the wreckage wasn't known.

Navy officials on Monday were attempting to flip the boat to retrieve the body and check for other possible victims. Special equipment has been brought in to lift up the boat, which is sitting some 45 meters (148 feet) beneath the surface, officials said.

Tourism is a vital part of the Thai economy, with the World Bank estimating the Southeast Asian nation generates about 12 percent of its gross domestic product from tourism receipts. Chinese tourists are a key driver of the industry, accounting for 9.8 million of the record 35.38 million tourists to visit the country last year.

Prime Minister Prayuth Chan-ocha, the country's military ruler, expressed his "profound sadness" in a letter to Chinese President Xi Jinping. In the letter released by the foreign ministry Monday, Prayuth said a full investigation is underway to find the cause of the tragedy and assured Xi his government is determined to ensure such incidents would not recur.

Prayuth arrived in Phuket on Monday to observe the operations and will visit Chinese relatives and survivors at a hospital.

Police said the captain of the Phoenix has been charged with "careless conduct leading to death" and could face more than three years in jail.

The captain of another boat that capsized on the same day and the manager of a travel agency that chartered the boat have also been charged for being careless leading to injuries. All the passengers from the second ship were rescued.

Tourism Minister Weerasak Kowsurat, who is in Phuket, has said the government will "spare no one" and will bring all those responsible to justice. Families of each victim could receive up to 1.4 million Thai baht ($42,000) in compensation, officials said.