South Korean prosecutors are seeking the arrest of members of the family that owns the operator of a ferry that sank last month killing hundreds of school children, an avoidable tragedy that rocked the country to the core.
Prosecutors may also seek the extradition of a son of the reclusive head of the family from the United States, an official said on Thursday.
The Sewol, overloaded and travelling too fast on a turn, capsized and sank on a routine journey from Incheon on the mainland to the southern holiday island of Jeju.
Of the 476 passengers and crew on board, 339 were children and teachers on a high school outing. Only 172 people have been rescued and the remainder are all presumed to have drowned.
Some of the crew, the captain caught on videotape in his underwear, abandoned ship as the children were told time and time again to stay put in their cabins.
They paid for their obedience with their lives.
Heartbreaking video shows them playing around as the ship started listing, joking about the sinking of the Titanic, when they had plenty of time to jump overboard.
But only two of the vessel's 46 lifeboats were deployed.
The prosecutors' pursuit of a son and a daughter of Yoo Byung-un, the head of the family that owns Chonghaejin Marine, the ferry operator, broadens the criminal investigation into the tragedy. The government has also started the process of stripping the company of the licence to operate ferries.
But it was not clear whether Yoo Byung-un himself, who ran the defunct commercial empire that was the precursor to the sprawling business interests that include Chonghaejin, might be called in for questioning.
Yoo's son, Hyuck-ki, who is believed to be in the United States, has failed three times to respond to a prosecution summons, an official said. Other close aides to Yoo are also believed to be abroad and have ignored summons.
"Since it is an important issue that has drawn public attention, we will do our best for their attendance and forcible extradition" said Kim Hoe-jong, second deputy chief prosecutor at Incheon District Prosecution Service.
Prosecutors arrested several officials of the ferry operator and its affiliates, including Chonghaejin's chief executive, on charges of negligence causing death and the sinking of a vessel on Thursday.
All 15 of the surviving crew members, including the 69-year-old captain, have been arrested and face charges of gross negligence amid accusations they abandoned the vessel without performing emergency escape procedures.
Yoo's two sons, Yoo Hyuck-ki and Yoo Dae-kyun, are majority owners of Chonghaejin Marine through an investment vehicle.
The prosecution is working with FBI and Homeland Security in the United States for possible extradition of Yoo Hyuck-ki, Kim, the prosecutor, said.
Prosecutors have also raided the shipping company's offices and financial regulators are investigating borrowings of the company and of businesses that are part of a wider holding firm.
Lawyer Son Byoung-gi, who has spoken for the family previously, did not immediately comment.
South Korea, Asia's fourth-largest economy and one of its leading manufacturing and export powerhouses, has developed into one of the world's most technically advanced countries, but faces criticism that regulatory controls have not kept pace.
Nearly 450,000 people have paid tribute to the victims at the altar set up near the school many of the children attended.
But the number of grieving family members keeping vigil in Jindo, where the search operation is centred, has dwindled with now just 35 of the 476 passengers still missing.
By Ju-min Park