Guajajara Indians "forest guardians" detain a logger during a search for illegal loggers on Arariboia indigenous land near the city of Amarante, Maranhao state, Brazil, September 17, 2019. Near midnight, a group of six Guajajara tribesmen with their faces painted for battle listen to the rumble of heavy trucks about 19 miles (30 km) from their village in the Amazon rainforest. REUTERS/Ueslei Marcelino

A Guajajara Indian and "forest guardian" detains a logger during a search on Arariboia indigenous land near the city of Amarante, Maranhao state, Brazil, September 17, 2019. They suspect a caravan of illegal loggers felling trees on their reservation. The police are not coming, but the natives have a plan to fight back. REUTERS/Ueslei Marcelino

A Guajajara Indian and "forest guardian" burns a truck used by loggers during a search on Arariboia indigenous land near the city of Amarante, Maranhao state, Brazil, September 17, 2019. The "forest guardians," as they call themselves, hurry to a choke point in the local network of rutted dirt roads and lay in wait, armed with rifles and handguns. REUTERS/Ueslei Marcelino

A Guajajara Indian "forest guardian" cooks birds at a loggers camp on Arariboia indigenous land near the city of Amarante, Maranhao state, Brazil, September 11, 2019. Loggers and ranchers have cleared land right up to the Guajajara reservation and crossed the border increasingly in recent decades. REUTERS/Ueslei Marcelino

A Guajajara Indian "forest guardian" sets fire to a loggers camp on Arariboia indigenous land near the city of Amarante, Maranhao state, Brazil, September 12, 2019. REUTERS/Ueslei Marcelino

Guajajara Indians who call themselves "forest guardians" have a meeting whilst on Arariboia indigenous land near the city of Amarante, Maranhao state, Brazil, September 11, 2019. REUTERS/Ueslei Marcelino