From Ammoland:

This response wasn’t the first time that FPC had used colorful language to push back against gun control, but it might be the first time that a Governor’s staff reported the organization to the police for a perceived threatening statement. Thanks to a Freedom of Information Act (FOIA) request by the Maine Wire, we now know the staff contacted Maine State Police’s Executive Protection Unit to investigate the tweet. The Executive Protection Unit is responsible for protecting the Governor, similar to how the United States Secret Service (USSS) is supposed to protect the President and former Presidents of the United States.