Once the investigation was completed, the panel concluded that the cause of the Sewol sinking could be either problems with the ship or an unknown external shock, Yonhap news agency reported.

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Problems that the ship could have face may include a sudden turn of the ship, excessive cargo load and inadequate refurbishing of the vessel that could have impacted its stability and buoyancy. External factors could have been collision with a submarine or other unknown object.

The panel was consisted of maritime experts and lawyers, and was divided over how the 6,800-ton vessel sank off South Korea while heading to the island of Jeju, on April 16, 2014. 304 lives died, most of whom were high school students who were on a school trip.

The panel submitted its investigation report to President Moon Jae-in and preserved the wreckage, in order to conduct a probe and to raise public awareness.

A final decision will be made on whether the vessel should be preserved, after getting feedback from families of the victims and others.