South Korea's defence minister said Friday that a torpedo might have sunk a warship near the tense North Korean border but cautioned that the investigation was incomplete."A torpedo or a sea mine might have been involved but a torpedo is a more realistic cause than a mine," minister Kim Tae-Young told parliament as divers resumed a search for 46 sailors missing from the 1,200-tonne corvette. Sailors operating the ship's sonar detection system had not detected any approaching torpedo, Kim said, adding: "Patience is needed until investigation results come out." A week after the disaster, officials are still groping for answers...