Argentine singer songwriter Facundo Cabral was shot dead Saturday by unknown gunmen who intercepted his car in Guatemala City. Authorities haven't determined a motive, but suggested that a concert promoter who was also in the car might have been the intended target. Cabral, 74, was an icon of Latin American folk and protest music ever since the 1970s. The presidents of Colombia, Ecuador and Venezuela expressed their condolences and Guatemala's Nobel laureate Rigoberta Menchu went to the site of the killing and wept. Guatemala has one of the highest murder rates in the region.