SEOUL, April 18 -- Arrest warrants were sought Friday for a captain and two sailors of the sunken South Korean ferry, which capsized and sank in waters off the country's southwestern coast Wednesday.

South Korean prosecutors filed for arrest warrants for the 69- year-old captain surnamed Lee, the third mate and the helmsman of the submerged vessel, which carried 475 passengers, mostly high school students, local media reported.

The captain, who was one of the first to abandon the ship, has already been arrested on charges of abandonment resulting in death, professional negligence and violation of rescue act. The two crew members were charged with violation of similar laws.

The additional punishment law on specific crimes was applied to the crew members as they escaped from the ship without making efforts to evacuate passengers first.

Earlier in the day, prosecutors said the third mate took the helm of the submerged ship at the last minutes before the ship sank into the waters.

The prosecutors told a press briefing that the third mate conned the ship at the last time when it was sinking and testimonies on where the captain was when the ship was sinking have been conflicting.

The rescued captain and crew members had been questioned by prosecutors to figure out why the ship sank. The captain came back to the steering room after the ship began tilting.

The 6,825-ton "Sewol" passenger ferry capsized and sank off Jindo Island, near the southwestern tip of the Korean Peninsula, on Wednesday morning.

The ferry disaster was believed to have been caused by a sudden turn in direction. The ship made an abrupt turn at about 8:48 a.m. local time Wednesday. The second turn was suddenly made four minutes later.

The Coast Guard received a distress signal from the ship at 8: 55 a.m., and the ferry remained afloat for some two and a half hours with its body tilting.

The abrupt turn was estimated to have moved some 180 cars and trucks and over 1,100 tons of cargo on the deck of the ship to one side, driving the ship to lean to the port side gradually.

While the captain and several crew members left the ferry, many passengers were left behind and failed to evacuate timely.

The ferry's regular captain who had been on leave was replaced by the arrested captain, who the ship's operator Chonghaejin Marine said is a veteran with eight years of experience on the Incheon-Jeju Island route.

Prosecutors searched the operator's headquarters, seizing documents and records.