They're demanding the independence of the Veneto region from the rest of Italy, and increasingly using violence: the radical separatists from the group known as "The Alliance."
The Veneto is one of Italy's wealthiest regions. But since the economic crisis, many people there are angry that their money is being spent to help the poorer south of the country. That's grist to the mill for the separatists, who are becoming increasingly radical. Recently the Italian police broke up a group which had acquired weapons from the Albanian mafia and planned to declare Venetian independence on St. Mark's Square.