South Korean police have formally arrested the captain and two crew members of a doomed ferry, on charges of deserting their passengers shortly after the vessel capsized Wednesday and sank.
Investigators are alleging the 69-year-old captain failed to carry out his duty to protect passengers when, according to witnesses, he was one of the first to leave the sinking ship. The ferry Sewol went down off the southwestern island of Jindo with 476 people on board.
Twenty-eight people are confirmed dead, and 274 others -- many of them high school students -- remain unaccounted for as hope diminishes for finding more survivors.
South Korea's Yonhap news agency said the captain also is suspected of instructing passengers to remain seated, even as the ferry began rolling onto its side and blocking escape routes.
Earlier Friday, police said a high school vice principal who led 325 students on a four-day ferry excursion committed suicide.
Police say 52-year-old Kang Min-kyu was found hanging by his belt from a tree near a building on Jindo island where survivors and relatives of the missing have been staying. A suicide note said Kang felt guilty for surviving while so many of his students remain missing.
Yonhap reported that a team of 21 divers tried to enter a cabin on the submerged second deck of the five-deck ferry, where most of the passengers are believed to be trapped 35 meters below the surface. But the report said the divers -- battling strong underwater currents -- surfaced 14 minutes later without having gained entry.
Experts say people theoretically could survive for up to 72 hours if there are air pockets in the submerged compartments.
Authorities have not established the cause of the disaster. But some survivors report hearing a loud impact noise before the vessel rolled onto its side and began sinking.
Heavy fog was reported in the area on Tuesday evening, but it is not known whether that was a contributing factor.
The Yonhap report says the third officer, who was steering the vessel at the time of the disaster, is suspected of making a sharp turn while piloting the ship through a narrow route. Investigators are quoted as saying the sudden turn may have caused 180 vehicles and nearly 1,200 tons of freight to shift and disrupt the balance of the vessel before it began to list.
U.S. President Barack Obama has sent his condolences to the families and says he will pay tribute to them during a visit to South Korea next week.