(ANSA) - Milan, October 12 - Domenico Zambetti, the former Lombardy regional executive councillor arrested two days ago for allegedly buying votes from the 'ndrangheta mafia on Friday said in a spontaneous statement that he had not known that his contacts belonged to the crime syndicate. He became aware of this fact only later when he started to receive threats, he said. Zambetti, a member of ex-premier Silvio Berlusconi's People of Freedom (PdL) party, is accused of vote buying, corruption and external participation in mafia association after paying two mobsters 200,000 euros for 4,000 votes (at 50 euros each) in the 2010 Lombardy regional elections. Zambetti has so far refused to answer questions before the preliminary-investigations judge, allegedly in order to first study the documentation relating to his arrest, his lawyer said. His arrest takes to 13 the number of councillors in the former Lombardy regional executive and assembly who are under investigation. They include Governor Roberto Formigoni of the PdL who is accused of corruption related to health contracts. On Thursday Formigoni bowed to pressure and dissolved the executive. He had said he would appoint a new, slimlined regional government over the next few days.