Brazilian police have denied reports that bodies were discovered in the Amazon belonging to a journalist and an indigenous expert.
Dom Phillips and Bruno Pereira went missing on 5 June.
Mr Phillips' brother-in-law told the BBC that the Brazilian embassy in the UK had informed the family that two bodies were found tied to a tree.
Police say they have only found some of their belongings and "biological material" which is still being tested.
The region's indigenous association Univaja, which first alerted authorities that the pair was missing, told the BBC that no bodies had been found.
Speaking to the BBC, Dom Phillips' brother-in-law Paul Sherwood said he received a call on Monday morning from a liaison officer at the Brazilian embassy. Mr Sherwood was told, in clear English, that two bodies had been found and the embassy was letting the family know before the press found out.
There was no misunderstanding, the brother-in-law said.
The news was reported by local and international media, citing family members of Mr Phillips.
But Brazil's federal police quickly released a statement saying that no bodies had been found, telling the BBC that there had been a miscommunication.
Local groups say both men had received threats for their work supporting indigenous rights in the region, where they were travelling by boat on a reporting trip.
Both Dom Phillips and Bruno Pereira were known for their deep knowledge of the region.
Mr Phillips had been living in Brazil for more than a decade and was a long-time contributor to the Guardian newspaper - he was in the area researching a book.
Mr Pereira, who was on leave from his post with the government's indigenous affairs agency Funai, was an expert on isolated tribes in the Amazon.
Days before the pair went missing indigenous groups say Mr Pereira was threatened for campaigning against illegal fishing in the area.
Speaking to the BBC, Mr Phillips' sister, Sian, said: "I think it's likely they've been ambushed by some illegal criminal activity there, possibly to do with illegal fishing."
It is an "incredibly distressing and awful situation", she added.
The region where they disappeared is home to around 6,300 indigenous people from more than 20 groups.
As well as clashes with fishermen catching protected stock, it has also seen incursions by illegal gold miners, loggers and drug traffickers who smuggle cocaine from neighbouring Peru.
Alarm over the men's disappearance was initially sounded by two indigenous rights groups, who said the pair had been travelling by boat in the Javari Valley to interview members of an indigenous group.
The area is located in the west of Amazonas state, near the border with Peru.