A state panel assigned to investigate the Sewol-ho ferry disaster has failed to pinpoint the exact cause of the sinking after an extensive probe.br Wrapping up their 13-month investigation on Monday,... the eight-member panel said the sinking could have been caused by problems with the ship or an unknown external shock.br The Sewol-ho ferry sank in waters off Korea's southwestern coast in April 2014,... killing 304 people.br Meanwhile, a final decision will be made on whether to preserve the ferry after consultations with the bereaved families and others.