The South Korean coast guard has released video footage showing the captain of a capsized ferry abandoning the vessel with hundreds of passengers still on board.
Lee Joon-seok, 69, wearing only his underwear and a jumper, is seen leaping from the top of the capsized ship onto a rescue boat.
Other crew members are helped out of the146-metrr (480ft) vessel, the Sewol, and brought to safety by a rescue team before the ship sinks further.
Coast guard official Kim Kyung-il said crew members failed to identify themselves as such to rescuers.
Lee has been arrested over allegations that a delay in ordering passengers to abandon ship caused hundreds to remain stuck inside as it went down.
All crew members responsible for the navigation have also been detained accused of negligence and of failing to help passengers in need.
Of the 476 people on board, only 174 survived. The official death toll in the disaster has reached 188 and divers are working to retrieve the more than 100 bodies believed to be still trapped inside the ship.
It has been alleged that Lee instructed passengers, the majority of whom were students on a school trip, to put on life jackets and stay inside while officers on the bridge were attempting to stabilise the vessel.
When the evacuation was ordered, half an hour later, the ship was tilting too severely for many people to get out.
"I am really sorry and deeply ashamed," Lee told reporters in the aftermath of the sinking. "I don't know what to say."
Lee later said he waited because passengers could have been carried away by the strong current and cold waters before help arrived.