Lanes entering the United States are shown closed during an investigation of a bomb threat at the Detroit Windsor Tunnel Thursday, July 12, 2012. The tunnel was closed to traffic after the threat was called in on the Canadian side, tunnel chief executive Neal Belitsky told The Associated Press. The call was made some time after 12:30 p.m. to the duty free shop on a plaza on the tunnel's Windsor side, tunnel executive vice president Carolyn Brown said. (AP Photo/Paul Sancya)
Lanes entering the United States are shown closed during an investigation of a bomb threat at the Detroit Windsor Tunnel Thursday, July 12, 2012. The tunnel was closed to traffic after the threat was called in on the Canadian side, tunnel chief executive Neal Belitsky told The Associated Press. The call was made some time after 12:30 p.m. to the duty free shop on a plaza on the tunnel's Windsor side, tunnel executive vice president Carolyn Brown said. (AP Photo/Paul Sancya)
An international commuter tunnel connecting Detroit to Windsor, Ontario, was closed for nearly four hours July 12 after a bomb threat was phoned in on the Canadian side. No explosives were found.