A backpack, laptop computer and other items belonging to British journalist Dom Phillips and indigenous expert Bruno Pereira have been found, police in Brazil said.
The pair went missing in a remote area of the Amazon a week ago.
Now, Phillips' mother-in-law has said she has lost hope that the pair will be found alive.
Phillips, 57, a contributor to The Guardian newspaper, and Mr Pereira, 41, an expert with Brazil's government agency for Indigenous affairs (Funai), disappeared on Sunday week after receiving threats during a research trip to Brazil's Javari Valley.
The two men were last seen in the town of Sao Gabriel, close to their destination, Atalaia do Norte.
“Objects belonging to the two missing persons have been found: a health card, black trousers, a black sandal and a pair of boots belonging to Mr Pereira, and a pair of boots and a backpack belonging to Mr Phillips containing personal clothing,” the Federal Police in Amazonas state said on Sunday.
The Amazonas Fire Department had told local media that personal effects possibly belonging to the missing men had been found “near the house” of Amarildo Costa de Oliveira, the only person arrested in the case and who witnesses said followed the men upriver.
Police said search teams on Sunday covered about 25 square kilometres with “thorough searches through the jungle, roads in the region and flooded vegetation”, especially in the area where a boat belonging to Mr Oliveira was found.
Earlier, authorities described Mr Oliveira, 41, as a suspect and said they were analysing traces of blood found on his boat.
The recovery of the men's belongings was hours after friends and relatives held a vigil on a beach in Rio de Janeiro.
“At first we had a crazy faith that they had noticed some danger and had hidden in the jungle,” said Maria Lucia Farias, 78. “Now, not any more.”
In a statement posted online and reported by The Guardian, Phillips mother-in-law said: “They are no longer with us. Mother Nature has snatched them away with a grateful embrace.
“Their souls have joined those of so many others who gave their lives in defence of the rainforest and indigenous peoples.”
Few of those gathered at the beach expressed much hope in the men's survival, especially after authorities said they had found a second boat with blood stains, and had located possible human remains, still being analysed.
“I used to come for walks on this beach with my uncle,” Phillips's nephew, Mateus Duarte, 13, said:
Phillips, who has contributed dozens of reports on the Amazon to The Guardian, had travelled to the Javari Valley while working on a book on environmental protection. Mr Pereira was his guide.
“We have to know what happened,” said Fabiana Castilho, 47, a friend of Phillips, who wore a T-shirt bearing a photo of the two. “We want an answer.”
Others in attendance said they hoped the men's disappearance would not be in vain.
“It should serve to raise awareness” about the environmental destruction of the Amazon, said Zeca Azevedo, Phillips's brother-in-law and Mateus's father.
“We have to honour their work.”
