Police are investigating whether an international network that pays poor fishermen to fish illegally in Brazil's Amazon is linked to the disappearance of a British journalist and an Indigenous official.
Freelance journalist Dom Phillips and Indigenous official Bruno Pereira were last seen a week ago near the Javari Valley Indigenous Territory, which sits in an area the size of Portugal bordering Peru and Colombia.
The two men were in the Sao Rafael community. They were returning by boat to the nearby city of Atalaia do Norte but never arrived.
After a slow start, the army, the navy, civil defence, state police and Indigenous volunteers have been mobilised in the search.
On Saturday, federal police said they were still analysing human matter found the day before in the area where the pair disappeared. No more details were provided.
The illegal fishing scheme is run by local businessmen, who pay fishermen to enter the Javari Valley, catch fish, and deliver it to them.
One of the most valuable targets is the world's largest freshwater fish with scales, the arapaima.
It weighs up to 200kg and can reach three metres. The fish is sold in nearby cities, including Leticia, Colombia, Tabatinga, Brazil, and Iquitos, Peru.
The only known suspect in the disappearances is fisherman Amarildo da Costa de Oliveira, also known as Pelado, who is under arrest.
According to accounts by Indigenous people who were with Pereira and Phillips, he brandished a rifle at them the day before the pair disappeared.
He denies any wrongdoing and said military police tortured him to try to get a confession, his family told the Associated Press..
Pereira, who previously led the local bureau of the government's Indigenous agency, known as FUNAI, has taken part in several operations against illegal fishing.
In such operations, as a rule the fishing gear is seized or destroyed, while the fishermen are fined and briefly detained. Only the Indigenous can legally fish in their territories.