RIO DE JANEIRO, Brazil (AFP)—American alt-pop singer and internet personality Oliver Tree was aboard one of two helicopters that collided Sunday mid-air in Brazil, leaving all six people aboard the aircraft dead, a police source told AFP. The source shared the manifest of each plane and said the victims could not be formally identified yet as they were badly burned in the crash. The helicopters collided in Recreio dos Bandeirantes, a western suburb of Rio de Janeiro, then plummeted into the parking lot of an electric car dealership, setting ablaze around 20 cars, firefighters said.