The fire that destroyed tens of thousand of rare books in the Anna Amalia Library in Weimar, Germany, last week may have been ignited by a faulty electrical cable, authorities said Tuesday. A final cause has not been identified, said German federal investigators working together with local and state police to pinpoint the source of the flames that destroyed some 25,000 books from the 16th, 17th and 18th centuries. Police official Rüdiger Schrehardt told reporters that a trail made by the flames on the third floor ran along an electrical cable. But "it could have originated elsewhere. The investigation is not closed," he said. The fire on Thursday night engulfed the roof and top floor of the 16th-century Rococo palace housing one of the country's largest collections of classical German literature.