A shadowy figure who terrorized the literary world for years by stealing unpublished manuscripts was finally nabbed by the FBI on Wednesday and outed as a 29-year-old Italian national and publishing professional named Filippo Bernardini, according to authorities. For five years, the mystery thief, dubbed the “Spine Collector” by New York magazine, used hundreds of fake email addresses and domains to dupe publishing figures around the world into handing over manuscripts, including some of the most hotly anticipated novels. Often he would slightly tweak someone’s email address so the victim would think it was a colleague or author asking for the prized document. But, bizarrely, the manuscripts never wound up on the black market or in ransom demands. Even odder, the thief stole both high-profile works and debut books by relative nobodies. The FBI arrested Bernardini, a rights coordinator for an international publisher in London, at JFK Airport and charged him with wire fraud and aggravated identity theft.