Fears have been mounting over the fate of Phillips, 57, a veteran contributor to The Guardian newspaper, and 41-year-old Pereira, an expert with Brazil’s government agency for indigenous affairs (Funai), since they disappeared last Sunday after receiving threats during a research trip to Brazil’s Javari Valley.
The far-flung jungle region has seen a surge of illegal fishing, logging, mining and drug trafficking.
The Amazonas Fire Department had previously told local media that personal effects possibly belonging to the missing men had been found “near the house” of Amarildo Costa de Oliveira, the only person arrested so far in the case and who witnesses say pursued the men upriver.
Police said search teams on Sunday covered about 25 square kilometers (10 square miles) with “thorough searches through the jungle, roads in the region and flooded vegetation,” especially in the area where a boat belonging to Oliveira was found.
Phillips and Pereira were traveling together by boat in the Javari Valley region in the far west of Amazonas state, conducting interviews for a book on environmental conservation.
They were last seen early 5 June not far from their destination, the river town of Atalaia do Norte.