Italy's most wanted mafia boss Matteo Messina Denaro was arrested on Monday in Sicily after being on the run for 30 years, Italian paramilitary police said. Denaro was captured at a clinic where he was receiving treatment for an undisclosed medical condition, said Carabinieri General Pasquale Angelosanto. Even while being a fugitive, Denaro was considered Sicily's Cosa Nostra top boss.