Nicholas Akerberg entered the courthouse in a helmet, gas mask, tactical boots, and sunglasses, Middlesex DA Marian Ryan’s office said.

Akerberg was arrested and transported to a hospital. He is charged with six counts of assault and battery with a dangerous weapon, five counts of assault and battery on a public employee, two counts of assault and battery on a police officer, assault, disrupting a court proceeding, disorderly conduct, bomb threat and intimidation.