Palermo, March 13 - Over 100 officers on Tuesday were executing arrest warrants for 12 people considered to have links with fugitive top Mafia boss Matteo Messina Denaro, sources said. The suspects are accused of mafia association and extortion, among other felonies. The operation is related to a probe that started in 2014 into the Vita and Salemi families, who are suspected of helping the fugitive mobster. Prosecutors said the Messina Denaro faction managed to get its hands on vast sums of money once handled by late Mafia-linked tax-collector cousins Nino and Ignazio Salvo. As well as helping to support Messina Denaro's life as a fugitive, much of this money was ploughed into the wind-farm business, prosecutors said. Messina Denaro, 55, has been on the run since 1993 and is considered Cosa Nostra's boss of bosses following the deaths of Bernardo Provenzano in 2016 and Salvatore Riina in 2017. He is on Europol's list of Europe's most wanted fugitives. He has not been seen in public in over 20 years. An informant in 2014 helped authorities update their facial composite of him.