NIAGARA FALLS, N.Y. (AP) — Authorities say there is no indication of a terrorist attack in the vehicle crash and explosion that left two people dead at a checkpoint on the American side of a U.S.-Canada bridge. The vehicle was speeding Wednesday from Niagara Falls, New York, toward the Rainbow Bridge, which connects the two countries across the Niagara River. The crash raised concerns on both sides of the border. But the FBI said its investigation found no explosive materials or “terrorism nexus.” It added that it had turned the matter over to local police “as a traffic investigation.”The incident prompted the closing of the border crossing and three others in the area. The other three later reopened.