Seoul, South Korea (CNN) -- The captain and three other crew members of the Sewol, the South Korean ferry that sank last month, have been charged with murder, chief prosecutor in the investigation Yang Joon-jin said Thursday.
The captain, Lee Joon-seok, along with the chief engineer, and the first and second mates, could face the death penalty if convicted of the charges. But it has been nearly two decades since the capital punishment was last carried out in South Korea.
The remaining 11 crew members have been indicted on charges of abandonment and violating a ship safety act.
The prosecutor's office said the captain and three crew members were charged with murder, because they didn't use the ship's facilities at their disposal -- such as life rafts, life vests and announcements to evacuate passengers.
Seven crew members were first to flee the ship, instead of carrying out their responsibility to save the hundreds that remained inside the ferry, the office said. Passengers were instructed not to move and to stay in place as the ferry listed.
The Sewol ferry sank en route to Jeju Island on April 16, killing 284 people and leaving 20 others still missing. Most of the passengers were students on a school field trip.
Obstacles in search efforts
South Korean officials have recovered 242 bodies found inside the ferry and 42 outside the ship.
The maritime police expects search efforts to become more difficult as the currents could strengthen over the next three days. Operations will be limited, Kim Seok-kyun, head of maritime police, said during a briefing Thursday.
The internal structure of the ship, which has been submerged for a month, is becoming weaker and more prone to collapse. Authorities are looking into the possibility of cutting into the exterior of the ship to make an entrance using the cranes situated at the accident site.
Conduct during sinking
On April 16, the order to evacuate ship was never given, prosecutors said. And none of the crew were prepared to deal with an emergency situation because they had never been trained for such a scenario.
A few days after the incident, Lee initially defended his actions, saying he had not evacuated passengers because the rescue boats had not arrived yet, and the tide was strong, and the water cold.
Footage of the captain in what looks like his underwear hopping into the arms of the rescuer, while hundreds of passengers remained inside the sinking ship, infuriated South Koreans.
Lee had not been at helm of the ferry when it started to sink.
The Sewol disaster caused widespread outrage in South Korea over lax safety standards and the failure to rescue more people as the ship foundered.
Investigators are looking at the overloading, the failure to secure cargo properly, the imbalance of weight on the ferry, and a sudden turn on the ferry as possible reasons for the Sewol's sinking.
Journalist Jung-eun Kim and CNN's Paula Hancocks reported from Seoul; CNN's Madison Park wrote from Hong Kong