Brazilian police said they have found personal items belonging to the missing UK journalist Dom Phillips and indigenous expert Bruno Pereira just hours after a plea for answers from their families, the BBC has reported.
The items include Mr Phillips' boots and a backpack with clothes in, as well as Mr Pereira's health ID card, a flip-flop, black trousers and boots.
The pair went missing while travelling by boat on a reporting trip in a remote Amazon rainforest on June 5.
Mr Pereira had recently received threats over his work against illegal fishing.
Mr Phillips' wife and mother-in-law say they now presume the two men are dead.
"They are no longer with us," his mother-in-law wrote on Instagram. The post was later shared by the journalist's wife.
Last week, the police found possible human remains in a river near the town of Atalaia do Norte. Experts have since been analysing the "organic material".
Blood traces found on a boat belonging to a fisherman, who has been arrested, are also being tested.
Another boat belonging to the suspect, named as Amarildo da Costa, was also discovered in the past 24 hours.
Mr da Costa, known locally as "Pelado", has been questioned and charged with illegal possession of restricted ammunition.
The authorities were helped by searches carried out by the indigenous communities.
The journalist's sister, Sian Phillips, made an emotional plea from her Lancaster home last week for the Brazilian government to find the two men.
And she also called on the UK authorities to put pressure on the Brazilian government.
"We want to carry on with the search," she said in a statement to the media during a gathering in front of the Brazilian embassy in London.
"We want to find out what is happening to them and we want anyone responsible for any criminal act to be brought to justice. We want a persistent deep and open investigation."
Both Mr Pereira, 41, and Mr Phillips, 57, who has written about threats to the Amazon for publications such as the Guardian and the Washington Post, are hugely experienced and planned their journeys thoroughly.