Still not saying why they consider it terrorism.
Man Commits Act Of ‘Domestic Terrorism’ After Driving Through Coast Guard Gate And Assaulting Personnel in Grand Haven, Michigan
From the article: According to Wood TV, the attack on the Grand Haven Coast Guard station is being investigated as a case of domestic terrorism due to it being an attack on a federal building. They have not found any immediate links to terrorism though.
Yeah they did. From your first posting: "Hawke had said the incident was being treated as "an act of domestic terrorism" because it occurred at a federal building, but that the investigation has not revealed any terror link."