American singer Oliver Tree was among those killed in a helicopter crash in Rio de Janeiro, Brazil, on Sunday, according to a police source. The crash resulted in no survivors. Tree was in the country as part of his world tour. Authorities have not yet released details regarding the cause of the crash or the identities of the other passengers. The incident occurred amidst ongoing investigations into similar helicopter accidents in the region. Further updates are expected as the investigation progresses and more information becomes available from Brazilian authorities. The news has prompted an outpouring of reactions from fans and fellow musicians.