Based on what we'd seen in Revenge of the Sith and A New Hope, the assumption among Star Wars fans was that "Ben" Kenobi had learned of Anakin Skywalker's survival sometime between the two movies.

Speaking with Empire Magazine about the scene in which Anakin strikes down Mace Windu being the defining moment in Anakin’s transition into Darth Vader, Christensen expressed, “That scene is the ...