American singer Oliver Tree died alongside five others in a mid-air helicopter collision over Rio de Janeiro, Brazil.The crash, which occurred during his world tour, caused a fire that destroyed multiple vehicles and is now under official investigation.His former partner Melanie Martinez and several high-profile industry peers paid public tributes to the musician's creative legacy and infectious spirit.Colleagues and fans worldwide are mourning the 32-year-old artist who became a global sensation for his distinctive musical style and creative projects.