SEOUL - South Korean prosecutors said Monday that a deadly combination of cargo overloading, illegal redesign and poor helmsmanship led to the April ferry disaster that claimed more than 300 lives, mostly schoolchildren.
The coastguard's botched initial response also contributed to the high death toll, the Supreme Prosecutors' Office (SPO) said, releasing the findings of a five-month-long probe into the disaster.
It backed charges and evidence presented at the ongoing murder trial of the vessel's captain and crew that the Sewol ferry was overloaded with cargo and not carrying enough ballast to balance the vessel correctly.
Investigators also found that a redesign in 2012 to increase cargo capacity had impaired the ship's stability, leaving it top heavy.
"The ferry had essentially lost its ability to maintain its balance," the SPO said in a press release.
At the time of the incident, the 6,825-tonne Sewol was carrying 3,606 tonnes of freight and cars, more than three times its recommended maximum cargo, the SPO said.
The poorly trained crew then made a sharper-than-recommended turn as the ship sailed through a strong current.
"Due to the helmsman's unskilled handling, the ship listed, sending cargo towards to one side, and then sank.
"The captain was not in the control room and let the helmsman take charge. His negligence was partly responsible," it said.
Captain Lee Joon-Seok and three senior crew members are accused of "homicide through wilful negligence" - a charge that can carry the death penalty.
Eleven other crew are being tried on lesser violations of maritime law.
As well as abandoning the ferry while hundreds were still trapped inside, the crew were accused of ordering passengers to remain where they were when the ship began listing.
Captain Lee is scheduled to testify in his trial for the first time on Tuesday.
He has insisted that the ferry owners are the real culprits as it was their decision to habitually overload the vessel.