A cattle rancher's son has confessed to arranging last week's murder of an ecologist and labor leader known worldwide for his efforts to preserve the Amazon rain forest, police say.

Police said Darcy Pereira, 21, told them he hired a professional killer to slay Francisco Mendes, who was shot Thursday as he stepped from his house in the jungle city of Rio Branco, 2,650 miles northwest of Rio de Janeiro.The local police official who was reached by telephone and provided The Associated Press with the information identified himself only as officer Calbi and would not offer further details.

TV Globo, the nation's principal private network, said Pereira's father was involved in a land dispute with Mendes, 44, who was known internationally for leading a campaign against destruction of the Amazon region.

In June 1987, Mendes was honored by the United Nations for his fight as head of the local rubber tappers' union to stop acres of rain forest from being cleared for cattle grazing.

Pereira turned himself in to the 4th Police Precinct in Rio Branco accompanied by a lawyer, according to TV Globo. It identified Pereira as the son of cattle rancher Darli Alves da Silva, who TV Globo reported was involved in a land dispute with Mendes.

Under Brazilian custom, the son does not always use his father's name.