Marvel Comics announced today that the killer of The Watcher will be revealed in Original Sin #6 by Jason Aaron and Mike Deodato, which is due in stores on July 16th.  The question of who was responsible for Uatu’s demise will be settled definitively in Original Sin #6, but the story is far from over since the person responsible for The Watcher’s untimely demise is now in possession of the knowledge that Uatu had guarded.
 
Marvel’s Original Sin crossover event is off to a strong, incentive fueled start with sales of over 150K on the miniseries’ first issue (see "Comics Down Slightly in May"), and, at this point, it appears to be the dominant crossover event of the summer.