Monster Truck Tragedy -- Three People Killed ... After Truck Drives Into Crowd

At least three people were killed during a monster truck event in the Netherlands Sunday when a driver lost control of his vehicle and plowed into a crowd of people.

The monster truck had just completed routine trick -- where it drives over several parked cars -- when it veered left, taking out a guard rail and dozens of spectators who were standing behind it.

The mayor of the town where the event took place told media that 3 people were killed -- including one child -- and 15 other people were injured.

One of the event organizers told local news he believes the problem could have stemmed from one of two things -- either the gas pedal got stuck or the brakes failed.

The driver is reportedly being questioned by police.