Captain Lee Joon-seok, 69, and two other crew members who abandoned ship have been arrested on negligence charges.
Their actions have been called "tantamount to murder" by South Korean President Park Geun-hye as the emotionally charged investigation and recovery of hundreds of bodies, many of them children from a single school, continues.
Four of the crew were paraded in front of Korean television cameras on Thursday and apologised for their actions in leaving the sinking vessel while passengers were still on board.
The three main suspects, the captain, a third mate and the helmsmen, have also apologised, according to a source who is directly familiar with the legal proceedings, but have not admitted liability.
According to the source, the three were asked whether they wanted to get their own lawyers, but did not take up the offer.
It was not immediately known why.
The lawyer appointed by the state had talked to the crew members for an hour ahead of a hearing to determine the validity of the warrant against them, the source said.
The source declined to be named due to the legal proceedings and the controversial nature of the case.