Crowds in downtown Bangor watched in horror on Thursday as the driver of an antique tractor was crushed to death after he fell into street and into the path of an antique firetruck during the city's annual Fourth of July parade.

Police say the male victim was operating a green tractor when he was struck in the rear by a vintage Bangor Hose Five Museum as the two vehicles turned right onto Water Street from Main Street at about 12:40 p.m. The man was killed instantly, according to police.

“It was awful. Just terrible,” Bangor Police Sgt. Paul Edwards said.

Police say initial reports indicate the fire truck's brakes may have malfunctioned, causing the vehicle to collide with the tractor.

The accident occurred in front of many spectators at the busiest part of the parade route. Grief counselors were brought if for witnesses.

Police have not released the names of those involved pending the notification of the victim's relatives.

The accident remains under investigation.

The death comes on the heels of an armed gunman in downtown Bangor delaying, and then diverting the route of, the annual parade.