ROME — Your college roommate is on Facebook. So are your cousins, colleagues and friends. But guess who else may find Facebook a great way to stay in touch? Some people in Sicily who know a few things about networking.

In recent weeks, Italian authorities have begun investigating Facebook discussion groups devoted to convicted Mafiosi, concerned that some members might be more than fans. A campaign calling on Facebook to remove pro-Mafia pages has gained momentum, and thousands of members have joined anti-Mafia groups.

The debate spilled over from civil society to online society after recent news reports revealed that more than 2,000 people had joined Facebook interest groups hailing Salvatore Riina, the so-called “boss of bosses” known as Toto, who was arrested in 1993, and his successor, Bernardo Provenzano, arrested in 2006. Both are serving multiple life sentences.

Such groups “are like sites that laud Hitler or Nazism,” said Rita Borsellino, whose brother, the magistrate Paolo Borsellino, spent his life investigating the Cosa Nostra before he was killed in 1992 by a car bomb that Riina was later convicted of ordering.

Borsellino said she thought Facebook was “damaged” by sites that glorified the Mafia. “These are people who are accused of serious crimes and are in prison,” she added.

Facebook’s member-generated groups encourage the free exchange of comments on a set theme. After receiving press attention, some groups disappeared, including “Toto Riina, the Real Boss of Bosses,” whose members wished Riina a merry Christmas and expressed their availability to work for him. Another group had called for the “immediate beatification” of Provenzano.

Facebook said it had taken down some Mafia-related content because it violated the site’s terms of use.

Kids having fun, or something sinister?

At the behest of anti-Mafia magistrates in Palermo, Italian authorities have contacted Facebook, which confirmed that it was working with the Italian officials who had opened an investigation.

“We’re taking it seriously without blowing it out of proportion,” said Maurizio De Lucia, a magistrate at the anti-Mafia prosecutor’s office in Palermo.

De Lucia said prosecutors were trying to determine whether members of pro-Mafia online groups were mostly “some kids who want to have fun” or gangsters looking for new ways to send coded messages to one another.

Last week, a member of Parliament’s anti-Mafia commission, Sen. Gianpiero D’Alia, called for a government investigation and urged his colleagues to remove their Facebook pages until the site took down pro-Mafia groups. “We can’t accept in virtual reality what we don’t accept in real reality,” D’Alia said in a telephone interview.

The motion was largely symbolic. By all accounts, the long arm of Italian law does not reach as far as Facebook’s servers in Palo Alto, Calif., and praising the Mafia is protected by free speech laws in both countries.

A spokesman for Facebook, who declined to be identified for an article on the Mafia, said the company would not disclose user information “until we have a good faith belief that an information request by law enforcement or private litigants meets applicable legal standards.”