On a sweltering afternoon in the wilds of the Brazilian Amazon, Edward Luz rode on the back of a motorbike into a forest clearing to confront a squad of combat-armed environmental police who, for their own safety, had helicoptered in. Luz is an anthropologist, a tall, powerfully built man of 43. He is a right-wing activist and, figuratively speaking, a hired gun. On that February afternoon in 2020, he wore tinted prescription sunglasses, a bushy beard and a radical haircut close-cropped on the sides. He did not have access to a helicopter. To get to the clearing, he traveled for eight hours by a ferry crossing and down muddy tracks from Altamira, a small city in the state of Pará on the far side of the wide brown Xingu river.