Lovers of Latin American music are mourning the murder of Facundo Cabral, the Argentine folk and protest singer shot and killed in Guatemala Saturday.

It's not clear why he was gunned down and his concert promoter may have been the target, according to some news reports. Still it's a terrible and ironic death for a man who was called a "messenger of peace" by the United Nations.

"Violence has become globalized. The violence...is a stupidity," Cabral told the Prensa Libre newspaper in a 2009 interview in Spanish. "Pope John Paul II said we had to globalize the solidarity. We are all brothers, and we live so much better when we respect each other."