An environmental consultancy working for an oil company withheld evidence of an “uncontacted tribe” where the company is operating in Peru’s Amazon, a leaked report obtained by the Guardian reveals.

The leak is acutely embarrassing for Perenco, based in London and Paris, because it has consistently claimed there is no evidence for indigenous people living without contact with the outside world near its operations and cites research by the consultancy, Daimi Peru, as proof.

The report was written by three anthropologists from the National University of the Peruvian Amazon (Unap) who were contracted by Daimi, which in turn was contracted by Perenco. The anthropologists list the evidence they found – “bent branches, footprints, women bathing in the rivers and crossed spears on pathways” – all of which was reported by local people..

“We found evidence of their existence,” says Teodulio Grandez, one of the anthropologists. “There were signs. We never said there weren’t any.”