Italian police arrested four suspected hackers Friday, accusing them of having taken control of the Italian branch of the Anonymous network.

The alleged hackers, aged between 20 and 34, were placed under house arrest near the northern cities of Bologna, Turin and Venice, and in the southern town of Lecce.

Six more people were placed formally under investigation and a total of 10 premises were raided at the conclusion of a two-year police investigation code-named “Tango Down.”

Investigators said the group, which had created a dominant cell within Anonymous Italy, was responsible for cyberattacks on commercial and government websites, including sites belonging to the Vatican, the Italian prime minister’s office, the defense ministry, the police, Bank of Italy and the national railway company Trenitalia.

“They were like a cancerous cell within the Anonymous organization,” said Ivano Gabrielli, a deputy police chief at the National Center for Computer Crime and the Protection of Critical Infrastructure (CNAIPIC), who helped coordinate the investigation. “They had taken over the brand and were using it for their own personal benefit,” Gabrielli said in a telephone interview. “It was a vanguard cell that was carving out a position of power at the head of Anonymous Italy. That’s somewhat anomalous in a supposedly anarchic structure.”

Some members of the group who are IT professionals offered their services to commercial companies to repair the damage caused by their own attacks, Gabrielli said.

The group had clashed with other members of Anonymous over ideological questions and had sought to consolidate its dominant position by denouncing some of its rivals to the police, he said. “They were responsible for reporting about 30 people to the authorities.”

Members of the group allegedly divided responsibility for different activities between them, some selecting targets, others carrying out the cyberattacks and yet others claiming responsibility for them.

The police investigation involved analyzing the technical characteristics of the attacks and the documents claiming responsibility for them, monitoring discussions on social media, the interception of electronic messages and phone calls, and infiltration of the group by undercover officers, Gabrielli said.

The suspects are accused of using the Internet for a criminal conspiracy, the first time such a charge has been employed in Italy, and face up to eight years imprisonment if convicted.

“The investigation was coordinated by the Rome prosecutor’s office and any trial will probably be celebrated in the capital,” Gabrielli said.

Gabrielli’s organization was embarrassed two years ago when a subgroup of Anonymous claimed to have stolen 8GB of secret documents from the CNAIPIC computer.

Most of the documents actually came from elsewhere, Gabrielli said.

Investigators said the four arrested suspects were IT professionals leading a double life. They worked as hackers mainly at night and even their families were unaware of their criminal activity, the online edition of La Stampa newspaper reported.