Italy's La Repubblica newspaper linked Benedict's resignation with a top secret 300-page dossier prepared by Spanish Cardinal Julian Herranz, Slovak Cardinal Jozef Tomko and Italian Cardinal Salvatore De Giorgi into the "Vatileaks" affair, which saw the Pope's former butler, Paolo Gabriele, arrested and jailed for stealing and leaking papal documents.
None of the three cardinals will take part in the conclave because they are over 80 years of age, but they are expected to brief those voting about their findings.
According to La Repubblica, the report was "an exact map of the mischief and the bad fish" inside the Holy See, with the cardinals finding that one faction of Vatican officials, "united by sexual orientation", had been subject to "external influence" from laymen with whom they had links of a "worldly nature", which the paper said was a reference to blackmail.
It quoted a source close to the cardinals as saying that everything centred on "non-observance of the sixth and seventh commandments", which forbid adultery (included homosexual sex) and stealing.
The report also mentioned numerous venues in and around Rome where clandestine encounters took place, including a sauna, a beauty parlour and a university residence.
Speaking just before he flew to Rome for the conclave that will elect Benedict's successor, Cardinal Pell, who read the full article, said: "I know nothing of the content of the report but whatever it contains it is clear that significant reforms are needed within the Vatican bureaucracy."
He praised Benedict for his "courage for commissioning such a report".
The cardinal said it remained to be seen how much of La Repubblica's report was accurate or whether it went beyond recycling material already on the public record.
But it was important, he said, that the Vatican press office responded "as I'm sure it will given recent reforms".