A massive police operation failed two years ago when the police's crucial informer, a Mafia turncoat, was murdered.
But now the carabinieri have struck once more against the ageing Mafia don. Police revealed yesterday that their operation, codenamed Orient, led to more than 50 arrest warrants in Sicily last week for leading Mafiosi accused of protecting Provenzano and included businessmen thought to have been in league with him.
The blitz followed a two-year inquiry into his activities by magistrates in Palermo, Catania, Caltanisetta and Messina.
The investigation began with the information of Luigi Ilardo, a Mafia turncoat and the man who led investigators temptingly close to their target. An hour before he was due to meet his minder in May 1996 Ilardo was gunned down.
But before he was killed he had already handed over a dozen precious letters written by Provenzano between 1994 and 1995.
The notes, full of grammatical errors and spelling mistakes, were examined by graphologists for their authenticity, and by psychologists to try to penetrate the mind of the man known as "the tractor". They proved a goldmine of information for police.
In the letters, Provenzano advised fellow Mafiosi on what strategy they should adopt to win lucrative contracts in construction and urged individual bosses to seek compromises with rival clans, telling them not to bother him with petty squabbles. He sent quotes from the Bible and kisses to the children of other known bosses.
Investigators say the correspondence proves that Provenzano is firmly in control of the Mafia's drug-running operations, extortion rackets and money laundering activities and that he took overall control of all the Sicilian Mafia families after the arrest in 1993 of the so-called "boss of bosses", Toto Riina. The letters suggest that Provenzano led a supposedly "moderate" wing of Cosa Nostra, which opposed launching full-frontal attacks on the Italian state, including the murders of Judge Giovanni Falcone and Paolo Borsellino in 1992. The moderates preferred more subtle tactics to keep their business empires intact.
The letters also gave investigators details of Provenzano's movements on the island of Sicily, which are especially valuable as they have little hope of spotting their prey.
The only photograph the police possess of Provenzano dates back to 1959. It shows a fair, clean-cut young man with his hair slicked back, gazing frankly at the camera.
A new "computer-aged" version was released in June, but judging from the marked difference between other recently arrested bosses and their photofits, investigators are essentially working blind.
To capture Provenzano would be the ultimate accolade for many senior officers close to retirement and a guarantee of promotion for younger, dynamic Mafia-busters.
General Mario Mori, head of the carabinieri special squad, is convinced they will eventually capture their man. "I have learnt to be patient through fighting the Mafia and its men, who more than anyone else have the virtue of patience," he said.
The hunt for the last great Mafia boss has ruined the careers of some of the police, partly due to the intense rivalry between the various anti- Mafia operations. Colonel Michele Riccio, who ran the informer Ilardo and hoped he would bring him to Provenzano, has since been suspended after being accused of possession of drugs and irresponsible management of his informers.