Inter is leading the league by one point over Roma going into the last game, but the club has had a clamorous end to the season after a series of faltering performances and dressing room clashes.
The Daily Telegraph says yesterday, the club's tailor, Domenico Brescia, 55, was revealed to be a convicted murderer who is close to the Crisafulli Mafia clan.
Brescia is also thought by police to be a cocaine dealer, and his conversations with several Inter players and Roberto Mancini, the manager, were recorded by investigators.
However, in one call Mr Mancini is recorded discussing Daniele Bizzozzero, a Mafioso associate of Brescia's who had fled to Monte Carlo and then Paris in a bid to escape the police.
"What happened to him," Mr Mancini is heard asking. "How was he arrested? I told him to stay [in Paris] and wait for a pardon."
Brescia then said that Bizzozzero was stupid, to which Mr Mancini replied: "He has always behaved well with me."
Questions were immediately raised about why Mr Mancini was discussing the fate of a criminal, and why he advised him to remain on the run. In other phone calls, Mr Mancini demanded "two coathangers" urgently and another Inter employee referred mysteriously to "packs of stuff" left in Brescia's car.
However, the police said they had no intention of prosecuting anyone at the club. The club cut all ties with Mr Brescia one month ago, when the full extent of his criminal past became known.
"We have only had commercial relations with Domenico Brescia," said a spokesman for the club. "He was our emergency tailor, seeing as his shop is very close to our Pinetina training ground. He has never been an Inter employee."
Brescia's lawyer, meanwhile, insisted he was close friends with several Inter players and had been visiting the training ground daily for 30 years.
The leak of the documents at such a sensitive time provoked a storm of outrage among Inter's fans, who insisted that the media was trying to unsettle the team.