SEOUL, South Korea - As divers finally get inside a submerged South Korean ferry to search for hundreds of missing high school students, a court Friday sought an arrest warrant for the ship's captain who survived by apparently taking one of the vessel's only lifeboats.

Rescue teams, fighting strong currents, have finally gotten into the upturned vessel and managed to pump air inside in hopes of reaching possible survivors.

Meanwhile, the vice principal of the school that arranged the overnight trip was found hanging from a tree, police said, in an apparent suicide. The school official, identified only by his surname, Kang, was on the island of Jindo, where rescued passengers have taken shelter.

Some 268 people, mostly high-school students, are still missing, as rescue teams report finding more bodies floating in waters off South Korea's southwest coast, pushing the death toll to 28, the Yonyhap news agency reports.

Of the 475 original passengers, 179 have been rescued, but 268 others, mostly high-school students on a school trip, remain missing.

The ship was taking 325 second year students from Danwon High School in Ansan, about 20 miles south of Seoul, on a four-day trip to the island of Jeju, a popular South Korean tourist destination.

The cause of the accident is still unclear, but a joint police and prosecution team said the captain of the Sewol, 69-year-old Lee Jun-seok, had left a third mate at the helm before the ferry began sinking Wednesday morning.

A court on Friday is seeking an arrest warrant for the captain and two other crew members, the Associated Press reports.

"The captain had a third mate be in charge of steering the vessel at the time of the accident," said Park Jae-uk, chief investigator of the joint team, according to Yonhap. "Though surviving crews have different testimonies about the situation, we've been investigating the captain as he was suspected to leave the steering room for an unknown reason."

Police and prosecutors are also investigating claims that Lee was among the first to leave his vessel, in violation of seafarers' law, said Yonhap, even as passengers were repeatedly told to remain inside.

Lee, wearing a hood pulled down tightly to cover much of his face at a news conference, made a brief apology Thursday to the passengers and their families as he was being questioned by coast guard officers.

Investigators are focusing on whether the boat, which was running late due to earlier fog, changed course too sharply, shaking cargo and cars loose and thereby shifting the boat off balance, reported South Korean media including the Chosun Ilbo newspaper.

Anguished parents, who have spent two nights gathered at a port on Jindo, the island closest to the ship, continued to accuse the government Friday of not doing enough to rescue their children. The government lied by exaggerating the number of rescuers, the families said in a statement read out by their representative at a Jindo gymnasium.

"There is no one explaining to us how the rescue operations are proceeding or directing us on what we should do. At this moment, our children would be screaming for help inside the ship," said the statement, reported the Korea Herald newspaper.

"Although our children were dying, there were no rescue efforts. They said they would do it later, but they made excuses, arguing tidal currents were too strong, and that their own safety would be threatened," the families said. "Citizens, this is the truth, the reality of the Republic of Korea. Please help save our children!"

Three massive cranes arrived Friday but it was unclear when they would be used to raise the vessel. Some divers managed to enter the ship Friday, where murky water leaves almost zero visibility, and rescuers have begun injecting oxygen inside the ship to have it floated and help potential survivors, said officials, according to Yonhap.

Prosecutors and police raided the boat's operator and owner Friday, reported the Korea Herald. About 10 officials from the joint investigation team took computer files and documents from the office of Cheonghaejin Marine Co. in Incheon, west of Seoul. The Sewol ferry, built in Japan in 1994, had extra decks fitted last year to accommodate more passengers, but passed recent safety inspections.