The Windsor Police say two Michigan men coming from Canada were stopped at the border due to a bag they had with them shortly after 5 p.m.
Inside the bag, police found a commercial-grade smoke grenade and brass knuckles. Brass knuckles are illegal in Canada, police are not sure about the smoke grenade.
Police reopened the tunnel at 9 p.m. Detroit police were telling drivers to take the Ambassador Bridge to go into or leave Canada at this time.
Windsor police is handling the investigation, due to the fact the package was found on the Canadian side of the border.
Stay with FOX 2 for more on this developing story.