Brazilian news outlets said the 26-year-old suffered a heart attack as he slept in his home in Juiz de Fora in the southeastern state of Minas Gerais.
Police told AFP that Melo's mother called emergency medical workers upon realizing her son was unconscious.
Melo was a star center at Syracuse University and was drafted by the Celtics in 2012.
But he only played in six games for Boston, before moving on to other teams and then returning home to play in Brazil in 2014.
source: news.abs-cbn.com
