Brindisi - Stormy weather in the Adriatic Sea thwarted efforts on Wednesday to tow a fire-ravaged ferry to Italy so authorities can investigate the blaze that killed at least 11 people and search the ferry for more possible dead.Ninety-eight people were still unaccounted for on Wednesday after a pre-dawn fire raced through the Norman Atlantic ferry on Sunday, Bari prosecutor Giuseppe Volpe was quoted as saying by the ANSA news agency.It's not clear if those people ever boarded the ferry - which left Greece on Saturday bound for Italy - if they were rescued, or if they died in the fire or the sea. Hundreds were rescued but the exact number of ferry survivors is still not known.Volpe said he hoped that Greek authorities would be able to say that many of those unaccounted for had arrived on various vessels in Greece.He also told Sky TG24 TV it was important to have the ferry towed to Italy "to see if there are bodies aboard...to ascertain what caused the fire and to see if safety measures were respected."Volpe said until the wreck was examined, he couldn't venture a possible cause for the blaze.The Italian captain of the Italian-made ferry, which was operated by a Greek company, was questioned in the southern port of Bari by prosecutors for more than five hours on Wednesday. Since a probe is under way, Volpe would not give any details about the questioning.Nearly 40 survivors finally stepped ashore on Wednesday in the Italian port of Taranto, brought by one of the cargo ships that rescued passengers from the flaming, smoke-shrouded ferry in the first hours of the maritime disaster. The blaze on the ferry's car deck sent people scrambling for their lives in the freezing cold, pelted by rain and buffeted by gale-force winds on the uncovered top deck.Video evidenceAmateur video made by two Turkish passengers who spent two days aboard the ferry showed clouds of black smoke belched up by the fire and bursts of flame as survivors lined up to be rescued by helicopters.In the video, obtained by The Associated Press, Italian rescue helicopters hoisted survivors one by one via cords or inside wire baskets. Passengers in orange life jackets and makeshift hats shifted their feet and shoved their hands in their pockets, trying to keep warm.Snow fell on Wednesday in usually temperate southern Italy, and winds whipping up to 70km/h made for rough seas as tugboat crew tried to secure the wreck."The shipwreck that we are towing is not anchored, and so it tends to move," said Giusieppe Barretta, owner of the tug company. He estimated once the ferry is secured, the tow to Italy could take up to 12 hours.The Norman Atlantic was closer to Albania's shore than Italy's and leaning slightly to the right, Barretta said. Smoke was still pouring out, probably from burning cars and tires inside, he said.