Highway patrol officers in the state of Parana told the Estado de Sao Paulo newspaper that the initial cause of the Saturday night accident was a collision between a car and a bus.
Officer Claudio Roberto Rafaelli said a motorcycle then collided with the car. The bus driver lost control of his vehicle and crashed into another oncoming bus. A pickup truck tried to avoid the pileup and rammed into some bystanders.
The police say they're investigating the original cause of the crash. Rafaelli says visibility was good at the moment of the accident.