I found an article Fresco Fiasco, that talks about his type of activity. Here's a snip from the article.
some Muslims in Italy are calling for the destruction of a medieval fresco in the Cathedral of Bologna on the grounds that it gives offence to Muslims.
The plan was foiled by Italian paramilitary police, according to the newspaper Corriere della Sera. The terrorist group was identified after police intercepted telephone conversations between several Tunisians and Moroccans with links to a Libyan known as Amsa, considered one of Osama bin Laden's chief operatives in Europe.
The cathedral, in the city's central Piazza Maggiore, is dedicated to Bologna's patron saint, San Petronio. The 15th-century Mohammed fresco, in the Bolognini chapel, shows the Prophet being set upon by demons. Four years ago, the chapel was occupied by Islamic immigrants during Ramadan in protest against the fresco, before police intervened.
The reports said special branch officers with the paramilitary Carabinieri force first heard of the plan in February. The plotters were said to be linked to Algeria's radical Salafist "Group of Prayer and Combat". The newspaper said the organisation, headed by an Algerian, was a splinter group of the Armed Islamic Group (GIA), which had contacts with Muslims in Bologna, Milan, Rome and Naples.
When they overheard the conversations, the police were hunting for a presumed North African terrorist cell based in Milan, which was believed to have become active after September 11, and which was thought to have made contact with Muslims in Britain, Holland and Belgium.