American alt-pop singer and internet personality Oliver Tree was among six people killed Sunday after two helicopters collided mid-air over Rio de Janeiro, according to a police source who spoke to AFP.

Authorities said the helicopters crashed in Recreio dos Bandeirantes, a western suburb of Rio de Janeiro, before plunging into the parking lot of an electric vehicle dealership. The impact ignited about 20 vehicles, firefighters said.

A police source shared the passenger manifests of both aircraft but said the victims could not yet be formally identified because their bodies were severely burned.

One helicopter was carrying five people, including Tree, while the second aircraft carried only the pilot.

Also aboard Tree's helicopter were a Brazilian music producer, an Argentine video director and Argentine YouTuber Gaspar Prim, known online as Gaspi.

Tree, 32, was known for his distinctive bowl haircut, eccentric online persona and hit songs including "Life Goes On," "Miss You" and "Alien Boy." He blended music, performance art, comedy and internet culture in his work and had more than 11 million monthly listeners on Spotify.

The singer had recently posted videos from Brazil on Instagram and performed in São Paulo on June 6 as part of an international tour spanning more than 30 countries. His next scheduled performance was in Lisbon on July 1.

Rio de Janeiro Mayor Eduardo Cavaliere earlier confirmed that foreign nationals were among those aboard one of the helicopters.

Burger King employee Thamires Santos, 27, said she heard “a really loud explosion” and felt the building shake before seeing helicopter debris scattered through the air.

Fire services spokesman Lt. Col. Fabio Contreiras said investigators are still determining how the collision occurred.

“Parts of the aircraft are scattered hundreds of meters away, so the information we have is still very preliminary,” Contreiras told CNN Brasil. “We really need to get the recordings and videos to understand exactly what happened.”

Rescue workers found one helicopter engulfed in flames among the parked vehicles, with five victims inside. The second helicopter, located about 100 meters away, contained only the pilot, who also died.

“Given the surrounding residences, the accident could have been far more tragic,” Contreiras said.

He also noted the challenges of extinguishing fires involving electric vehicles because lithium-ion batteries release toxic gases and intensify the blaze.

Brazil has recorded 84 aircraft accidents so far in 2026, excluding Sunday's collision, according to the Center for Investigation and Prevention of Aeronautical Accidents (CENIPA). Those incidents have resulted in 25 deaths.