Investigators are baffled after a 34-year-old man drove his pickup truck through a Coast Guard station gate Sunday morning in Michigan and assaulted personnel after saying he had packed his vehicle with explosives, WZZM-TV reports. 
The man, whose identity has not yet been released, was subdued and arrested at the Grand Haven station.
“The suspect is not from Grand Haven,” Hawke told reporters. “We’re unsure, unclear on whether he is acting alone or not. The investigation is rapidly expanding into other areas of Michigan. No indication of a motive at this time. That part of the investigation is still ongoing.”
Authorities found no explosives.
No one was serious injured.