Brazilian police arrested another five people in connection with the murders of British journalist Dom Phillips and Brazilian indigenous activist Bruno Pereira on Saturday, and said that one of the suspects already in custody was likely the leader of an illegal fishing mafia based in the Amazon region.
Three of those arrested in operations near Brazil's borders with Peru and Colombia were wanted for helping to bury the bodies of Phillips and Pereira, although they gave few details.
All three are related to Amarildo da Costa Oliveira, one of three men charged last month with double murder in a case that shocked the world and highlighted growing insecurity in the densely forested region.
Phillips, 57, and Pereira, 41, went missing on June 5 in the Javari Valley in western Brazil, after Phillips had arranged to report a book about sustainable development.
Pereira, a former official with Brazil's state Indigenous agency, knew the area well and was helping the Briton with his research.
The men were ambushed early in the morning as they went down the Itaqua River on their boat. The police believe their assailants shot dead and then carried their bodies into the jungle, where they buried them in the hastily dug grave.
Two of the suspects confessed to the crime and led police to where they had buried their bodies.
The police believe that the killers were worried that Pereira had photographs and evidence that they were fishing in banned areas for endangered species, including turtles and pirarucu, one of the world's largest freshwater fish.
One single pirarucu can fetch up to $1,000 at markets in Brazil and Colombia, and police believe criminal mafias partner with impoverished local fishers to hunt the animals, often in Indigenous reserves where access to outsiders is prohibited.
One man was arrested last month for using false ID papers and on Saturday said they had identified him as Ruben Dario da Silva Villar, AKA Colmbia. The police found strong indications that Col mbia is the leader and financier of an armed criminal association dedicated to the practice of illegal fishing in the Javari valley and responsible for the sale and export of a large amount of fish, the federal police said in a statement.
Local news reports said da Silva Villar provided the local fisher with boats, motors and bait.