RIO DE JANEIRO -- Brazil’s federal police announced Friday that they had arrested a man to investigate possible connections with illegal fishing in an area where Dom Phillips, a British journalist, and Bruno Pereira, an Indigenous expert were murdered just over a year ago.

This is the fourth arrest made since the start of the investigation. Police said Friday in a press conference that they were continuing the investigation to "see if other people are involved".

Authorities stated that they are investigating whether the man who was arrested for presenting false documents on Thursday is connected to illegal fishing operations in Javari Valley Indigenous Territory. This territory borders Peru and Colombia. His identity is not known.

This region is rife with conflict between Indigenous tribes, and poor fishermen who invaded the Javari Valley to capture arapaima turtles and other game. Pereira, an official from Brazil's Indigenous affairs Bureau, was involved in fighting these invasions for many years and received numerous threats.

Phillips was on a trip with Pereira to research a book on how to save the largest rainforest in the world.

The bodies of the victims were discovered by Amarildo da Silva da Costa de Oliveira (nicknamed Pelado), who confessed to killing Phillips, 57, as well as Pereira, before leading police officers to their remains. Police also arrested Pelado's brother, fisherman Oseney da Costa de Oliveira.

This week, a federal judge took over the case that was previously in the state's hands.