Reuters - which isn't in the business of spreading baseless rumors - stated this morning, "Google is investigating whether one or more employees may have helped facilitate a cyber-attack that the U.S. search giant said it was a victim of in mid-December, two sources told Reuters on Monday."
More specifically, people who actually work for Google in China are said to be under the microscope.
From a how-did-they-do-it perspective, involvement on that end of things would make a lot of sense. It could explain why Google's ready to abandon China, too, since the corporation probably isn't equipped to fight the Chinese government (which most experts believe was behind the attacks) at every turn.
Still, any inward-looking investigation may just be a matter of Google covering its bases. It's a little too early to start comparing this matter to some spy thriller just yet.