The main defendant in the murder trial of ecologist and union activist Chico Mendes stunned a courtroom Wednesday by confessing to the crime during the first day of the proceeding.

During questioning by Judge Adair Longhini, Darci Alves Pereira admitted shooting Mendes in an ambush in 1988.As bailiffs led Pereira from the courtoom in this remote Amazon jungle town, Longhini stopped them and questioned the defendant again.

Pereira paused, then looked up and said, "I confess."

The confession was a stunning development in a trial that has drawn international attention and is seen as a test of Brazil's commitment to protecting its rain forests.