The couple first reported missing in the Javari Valley on Sunday and reportedly received death threats a few days earlier. Phillips and Pereira were researching a book project on conservation efforts in the area, which authorities have described as “complicated” and “dangerous.” The region is under increasing threat from illegal miners, lumberjacks, hunters and international drug traffickers who exploit its vast network of rivers. According to police, five other people have also been questioned in connection with the missing couple. The Federal Police Crisis Committee said it was conducting a “river search and aerial reconnaissance” over the past 24 hours in Rio Itakuai.