At the end of a long, bare corridor in Milan's fascist-era Palace of Justice, there is a special department with its own plaque: District Anti-Mafia Office.
But the plain-clothed officers within aren't just tied up fighting organized crime. Many top investigators here have turned their anti-Mafia skills to rooting out a new kind of criminal in their midst: Islamic terrorists.
"In some ways, the job is the same," says Guido Olimpio, coauthor of "Milan-Baghdad," a book about investigating Islamic terrorism in Italy. "You know who the Mafiosi are. But you don't have the proof to arrest them. It's the same with today's terrorists."
Italy's success in breaking the "omertà," or the Mafia's code of silence, has been key to convicting Mafiosi. Special legislation offered Mafiosi a tempting package of police protection, reduced sentences, a new identity, and a new life - if they collaborated with police.
Middlemen with a criminal record were the easiest to win over. Hundreds of "pentiti," or turncoats, helped break some of the most powerful Mafia clans in the 1980s and 1990s.
But winning over the "pentiti" among Islamic terrorist cells, experts say, is a much harder task. Only two have been found in Italy so far.
"It is much harder to find members of the Muslim community willing to collaborate," says Milan prosecutor Armando Spataro, who tracked down Italy's left-wing terrorist Red Brigades in the 1970s and 1980s, and later the Mafia. This is partly due, he says, to language and cultural barriers. But it also stems from the difference in ideology between Italy's old and new enemies.
"With the Mafia, collaborators risked being killed. But they were reassured by police protection," he says. "Islamic terrorists believe they will reach paradise if they kill infidels. So there is a fear that if they betray, they will lose that prize. It's hard to convince people to give up the chance of eternal life."
Until investigators have better tools to bridge the language and cultural barriers, their chances of penetrating the ranks of Islamic terrorist networks in Europe are slim, says Mr. Olimpio.
In a nation where immigration is a relatively recent phenomenon, there are few fluent Arabic speakers available and many of them are too afraid to work with police. In Milan, whose main mosque has been labeled by the United States Treasury as "the main Al Qaeda station house in Europe," magistrates have only 10 interpreters to work with, and no funds for more.
Still, "if terrorism is a disease, Italy has already developed the antibodies," says Mr. Spataro. "We have a culture here of fighting major organized crime. The difference is that in the past we were able to identify potential victims and protect them. Now everyone is a potential victim."
Italy's anti-Mafia laws covering phone tapping, surveillance, and interrogation provide a framework for the country's counterterrorism investigations. But Spataro says the key to successful counterterrorism is rapid exchange of information between investigating teams inside Italy and internationally.
In that sense, Italy's counterterrorism units still have a lot to learn from their anti-Mafia past. So far, investigators working in the country's 26 districts have no centralized coordination or source of information on suspects.
"When magistrates meet, they swap amateur CDs full of data, because to this day there is no database they can consult to find out if a suspect is under investigation elsewhere," says Spataro, complaining that there are no funds for better resources, "If I want to find that out, I have to phone each prosecutor's office one by one."
Since 7/7, Italy has been reviewing its laws and its counterterror strategy. The country, which has almost 3,000 troops in Iraq, fears it could be the next target for terrorist attacks. Thirteen thousand potential target sites have been identified, including the Vatican and the Leaning Tower of Pisa. And legislation is being prepared to extend the period during which suspects can be detained for identification without charges.
But many say Italy's past experiences show that legislation is not the key to catching the enemy.
"Patience above all is the useful thing Italy learned with the mafia," says Olimpio. "Often, the boss is out of sight. But if you follow his foot soldiers for long enough, they lead you to him in the end," he adds. "You pick up a cent and you turn it into a dollar."