U.S. determines North Korea behind Sony attack as studio pulls movie

By Eric Kelsey, Lisa Richwine and Piya Sinha-Roy LOS ANGELES (Reuters) - A U.S. government source said investigators had determined North Korea was behind a cyberattack on Sony Pictures as the studio pulled all plans to release its comedy, "The Interview," about an assassination attempt on the North Korean leader. Hackers who said they were incensed by the film attacked Sony Corp last month, leaking documents that drew global headlines, and now they have forced an apparently unpreceden