In 1998, the man was caught on video during a chance encounter
The man, whose name was not known, had lived in total isolation for the past 26 years.
He was known as Man of the Hole because he dug deep holes, some of which he used to trap animals while others appear to be hiding spaces.
His body was found on 23 August in a hammock outside his straw hut. There were no signs of violence.
The man was the last of an indigenous group whose other remaining six members were killed in 1995. The group lived in the Tanaru indigenous area in the state of Rondônia, which borders Bolivia.
The majority of his tribe were thought to have been killed as early as the 1970s by ranchers wanting to expand their land.
The Man of the Hole is thought to have been about 60 years old and to have died of natural causes.
There were no signs of any incursions in his territory and nothing in his hut had been disturbed, officials said, but police will still carry out a post-mortem investigation.