U.S. singer Oliver Tree among six killed in helicopter crash in Brazil The Washington PostAmerican singer Oliver Tree listed aboard helicopter involved in fatal midair collision in Brazil CNNOliver Tree's Ex Melanie Martinez Remembers The "True Artist" — Kid Cudi, Bebe Rexha & More Pay Tribute DeadlineSinger Oliver Tree Is Said to Have Died in Collision of Helicopters in Brazil The New York Times
