The search continues for British journalist Dom Phillips, originally from Lancaster, and local indigenous expert Bruno Pereira, who are missing in Brazil.
The pair went missing while travelling by boat in the Amazon rainforest on Sunday.
Dom's family, who live in Lancaster, have appealed for his safe return.
Dom Phillips, a freelance journalist who has written for The Guardian, The Washington Post, The New York Times and others, was last seen on Sunday, travelling deep into a lawless part of the Amazon rainforest with an indigenous expert.
Brazilian police searching for a British journalist and an indigenous expert who vanished in a remote part of the Amazon rainforest say blood has been found on a boat belonging to a local fisherman who has been arrested.
Dom Phillips, a freelance journalist who has written about Brazil for The Guardian, The Washington Post, The New York Times and others, was last seen on Sunday, travelling deep into a lawless part of the jungle with Bruno Araujo Pereira, a former official with federal indigenous agency Funai.
Dom Phillips
The pair were last seen over the weekend in Javari Valley of Amazonas state - near the border with Peru.
According to The Guardian, Mr Pereira had received a number of threats from loggers and miners in the region.
Two Amazonas state police detectives directly involved in the case told Reuters news agency illegal fishing and poaching were likely behind their disappearance.
Police in the town of Atalaia do Norte questioned several fishermen as witnesses and arrested one of them, a local man called Amarildo da Costa, known as "Pelado", who was one of the last people to see the two men.
After searching Mr da Costa's boat for "possible genetic material", one of the detectives in the case said police were now investigating whether the traces of blood found were human or animal.
His lawyer, Davi Oliveira, said his client was not involved in the disappearance of Mr Phillips and Mr Pereira and was only engaged in legal fishing.
A handout photo made available by the Brazilian Federal Police shows forensic experts examining a boat with traces of blood from a suspect in the disappearances of British journalist Dom Phillips, a contributor to The Guardian newspaper, and Brazilian indigenist Bruno Araujo Pereira, who have been missing since 05 June in Vale Do Javari, Brazil, 09 June 2022.
The wild, unruly Javari region where the pair were last seen is home to the world's largest number of uncontacted indigenous people.
It has also lured cocaine smugglers, as well as illegal hunters and fishermen who travel deep into the Javari Valley to find protected species - such as the pirarucu fish - which is sold in regional markets.
Javari has grown increasingly tense and perilous in recent years, and in 2019, Maxciel Pereira dos Santos, who worked with Funai to shut down illegal fishing in the valley, was shot dead in Tabatinga.
Politicians, celebrities, journalists and activists have urged Brazil's president Jair Bolsonaro and his government to intensify efforts to find Mr Phillips and Mr Pereira.
Brazilian justice minister Anderson Torres said he had told British foreign office minister Vicky Ford that Brazil would keep up the search for Mr Phillips until it had exhausted all possibilities.
Mr Torres said he had 300 people, two aircraft and 20 boats conducting the search in what he called a "very difficult region".
"Even if you have 30 aircraft, one million people, it may not work," said Mr Torres, who was also pressed to maintain the search at the Summit of the Americas in Los Angeles by US climate envoy John Kerry.
Sian Phillips together with Gareth Phillips, siblings of missing journalist Dom Phillips hold a placard and a rose, as demonstrators protest following the disappearance, in the Amazon, of their brother Dom Phillips and campaigner Bruno Araujo Pereira, outside the Brazilian Embassy in London, Britain, June 9, 2022.
Mr Phillip's family has urged the government to act.
Paul Sherwood, the partner of Mr Phillips's sister Sian, wrote on Twitter: "We implore the Brazilian authorities to send the national guard, federal police and all the powers at their disposal to find our cherished Dom.
"He loves Brazil and has committed his career to coverage of the Amazon rainforest. We understand that time is of the essence so please find our Dom as quickly as possible."
Sian Phillips told Sky News she is concerned there is illegal logging and drug trafficking in the area where he disappeared.
"I'm very anxious. I'm desperately worried. It's your worst fear," she said.
"We need everything thrown at this. We want UK officials to put pressure on the Brazilian authorities to act."
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