They accused the authorities of failing to produce such information as navigation record which helps accurately probe the cause of the warship sinking.

They charged that the authorities have not yet opened to the public the animation file showing what happened the moment the warship sank under the pretext of keeping "military secret", adding that they have not produced any material evidence proving that the fragments, they claimed were retrieved from the waters where the case took place, are those of a torpedo of the DPRK.

The "results of investigation" still remain skeptical, they noted, demanding that the authorities open to the public information about the case as early as possible.