The Department of Justice has brought on Susan Athey, Stanford University professor and former Microsoft economist, as the agency ramps up its antitrust efforts.

According to The Seattle Times, Athey joins the DOJ as its top antitrust economist with a view to leveraging her expertise on the economics of internet platforms. The DOJ has been looking specifically at both Google and Apple, and it’s believed Athey’s focus will largely be on those two companies, according to the Times’ sources.

In addition to being a professor at Stanford University, Athey served as an advisor for Epic in its court case against Apple. She also has nearly a decade’s experience helping Microsoft in its antitrust battles with Google.