Without knowing what investigators found, the ultimate importance of the raid is unknown, but I can't think of an instance where the President's personal lawyer had virtually every place he worked served with a search warrant. This is unprecedented.
Michael Cohen reminds me a little bit of
Michael Clayton, a movie where George Clooney plays a corporate 'fixer' lawyer, the guy that makes all of the problems for wealthy clients go away. He starts to have something of an epiphany that it doesn't matter if you drive an S-Class Mercedes, you're still just a bag man, which means you can sometimes be a loose end. I imagine that's how Cohen is feeling right now.
It's also important to note that the search warrant did not come from Mueller. Mueller forwarded the information to the DOJ. My understanding is that this was referred to the Southern District of New York. Rob Rosenstein evidently decided that the information did not fall under the mandate of Mueller's investigation, and made the referral.
So in the course of his investigations, it is possible that Mueller came across information of a potential crime that Michael Cohen may have committed that are not apart of his investigation. He still has an obligation to inform DOJ, which makes the determination as to which office should receive the information.
