ROME -- Matteo Messina Denaro, a brutal Sicilian Mafia boss who was Italy's most wanted criminal before his capture on Monday, had been on the run for 30 years. Here are some key facts about his arrest and what it means:   Why is the arrest so important?   Messina Denaro, 60, was the last runaway member of a generation of mobsters who masterminded a string of bombings and murders that terrorized Italy in the early 1990s. His arrest finally brings closure to that dark era, shatters a symbol of resistance to the Italian state and could reveal Mafia secrets in the unlikely event that Messina Denaro agrees to talk to investigators. He was involved in dozens of kil...Keep on reading: How top Mafia boss Messina Denaro escaped justice for 30 years