Assailants shot and killed a rural union leader who had defied powerful sugar barons in northeastern Brazil, police said Friday.

Police said Jose Helio da Silva was shot down in a sugar cane field Thursday near the Farm Workers Union in Palmares, a sugar-producing town in Pernambuco state, 1,600 miles northeast of Sao Paulo.The slaying occurred on the second day of the trial of two ranchers accused of ambushing and killing environmentalist and union leader Chico Mendes in Brazil's Amazon region in 1988. The trial has focused worldwide attention on a cause advocated by Mendes, preserving the Brazilian rain forest from ranchers and farmers who are cutting it down and, according to some environomentalists, thereby threatening a vital ecosystem and the lifestyles of jungle residents.