Two sons of a cattle rancher who favored clearing the Amazon for grazing have been arrested in the killing of an ecologist who fought to preserve the jungle, police say.

Brothers Aleci and Oloci Alves da Silva were captured after a gun battle with police Tuesday night on their family ranch in Xapuri, the jungle town where Francisco Mendes was gunned down last week, Deputy Minister of Justice Luis Fernando Eichenberg said. Oloci was wounded in the shootout.The two are sons of Darly Alves da Silva, a rancher who was angry over Mendes' campaign to save the rain forest. Mendes had said the rancher threatened to kill him.

The internationally known ecologist, who organized jungle workers to try to stop destruction of the rain forest by plantation owners, was fatally shot Thursday outside his home in Xapuri, 2,650 miles northwest of Rio de Janeiro.