KYRA PHILLIPS, CNN ANCHOR: The immediate crisis may be over, but the search for answers is just beginning, and that initial search is zeroing in on the nation's heartland and three power lines owned by FirstEnergy Corporation. Our John Zarrella has that.</s>JOHN ZARRELLA, CNN CORRESPONDENT: The early speculation had been that the blackout began somewhere here in northern Ohio, but that may be changing, at least to a degree. Reports coming out today that a Wisconsin software company detected fluctuations in the voltage on the grid as early as Wednesday -- not necessarily significant, except the duration of time those fluctuations existed was significant. The Midwest ISO - that's the Independent Transmission System Operator -- is looking into that to see if there is any relevance. Midwest ISO is also saying that they don't believe that the cause of the blackout could have been simply four transmission lines here in Ohio that went down shortly before the blackout began. That had been the early speculation. And, FirstEnergy, the company that owns those four lines and co- owns one of them with another company, is saying they believe that other things were going on simultaneously outside of their service area; that it had to be more than their four power lines, their four transmission lines that caused the major blackout. John Zarrella, CNN, East Lake, Ohio.
Initial Investigation into Power Outage Zeroing in on Ohio