The FBI has determined the car explosion at the U.S.-Canada border Wednesday was not a terrorist attack.

The investigation was concluded a few hours after the explosion, which killed two people at a border checkpoint. The car moved through an intersection, hit a median, and went airborne before exploding at the Rainbow Bridge at Niagara Falls. 

“A search of the scene revealed no explosive materials, and no terrorism nexus was identified,” the FBI’s Buffalo office stated. “The matter has been turned over to the Niagara Falls Police Department as a traffic investigation.”

The Rainbow Bridge, along with three other border bridges, was closed as the investigation was concluded. President Joe Biden and Canadian Prime Minister Justin Trudeau were briefed on the explosion.

The incident took place the day before Thanksgiving, one of the most traveled days in the country.

New York Gov. Kathy Hochul said at a press conference that “there is no sign of a terrorist activity in this crash.”

The two people who died in the explosion were a married couple, the Associated Press reported.

Rickie Wilson, a Niagara Falls tour guide, said he was shocked to see the car take flight. 

“I first thought it was an airplane. It looked like slow motion,” he said. “I said, ‘My God, it’s a car. It’s a vehicle, and it’s flying through the air.’”

The Niagara Falls Police Department’s Crash Management Unit is taking over the investigation as a traffic incident. 

 “Due to the complexity of the incident, the investigation will take some time to complete,” the department said in a statement.