A round of arrests this week, inspired by information supplied by gangsters who have agreed to co-operate with the police, suggested corruption at the club went deeper than previously suspected.
Until now only Maradona has faced criminal charges for his behaviour during what many fans considered golden years for the club. Now prosecutors in Naples have summoned virtually all the squad for questioning, along with players' wives and, according to Italian press reports, have extracted several confessions.
This week the prosecutors arrested two local hoodlums suspected of peddling cocaine to as many as a dozen team members. They have also issued a warrant for the arrest of Guillermo Coppola, Maradona's former personal manager who is on the run from police in his native Argentina.
Coppola was recently spotted by a television crew in the Uruguayan resort of Punta del Este, where he has taken refuge following accusations that he ordered the murder of a prominent Buenos Aires night-club owner and suspected drugs trafficker.
Back in the 1980s, the prosecutors allege, Coppola played a role in distributing drugs to the players at Napoli.
The case against Napoli has been pieced together from hundreds of interviews with petty gangsters, call girls and past and present club officials. There have been tales of orgies on yachts, wild nights at a discotheque in the hills above Naples, sumptuous dinners with high-ranking members of the Camorra, the Neapolitan mafia, and - most notoriously - a party on the liner Achille Lauro to celebrate winning the 1990 Italian championship.
The two most fertile sources of information recently have been Pietro Pugliese, a former Camorra member who turned state's evidence after admitting to a string of murders, and Marco Fienga, a convicted drugs trafficker.
Their most serious allegation is that Napoli threw a game at the end of the 1987-88 season in exchange for favours from the Camorra, whose bookmakers stood to lose a fortune if Napoli won the championship, which went to Milan.
Prosecutors will have to decide how to follow up the allegation. Judicial sources in Naples said yesterday they might question Corrado Ferlaino, the president of the club at the time, and Ottavio Bianchi, the team's trainer.
Maradona left Napoli in disgrace after allegations of drug-taking were first levelled against him in 1990. Banned for three years for cocaine use, he fell definitively from grace when he failed a drugs test at the 1994 World Cup. He is now coaching an Argentinian side, Racing Club, and has refused to talk to journalists about the latest allegations.