Charges were laid last week after a camo-wearing man with a handgun was seen near the Howard Watson Nature Trail and Highway 402.
Home Depot and other businesses were locked down and city and provincial police swarmed the area, arresting a 23-year-old Sarnia man.
The gun turned out to be a BB gun, but a search of his home produced a 9mm pistol, three shotguns and a rifle.
The man was charged with possessing weapons dangerous to the public and causing a disturbance.