Palermo, May 29 - Italian police on Wednesday arrested for suspected tax evasion a key witness in a trial into alleged talks between the Italian State and the Mafia to stop an early 1990s bombing campaign that claimed the lives of heroic anti-Mafia magistrates Giovanni Falcone and Paolo Borsellino. Massimo Ciancimino is the son of the first Italian official to be convicted of Mafia ties, in the 1980s, late Palermo mayor Vito Ciancimino. Massimo Ciancimino has claimed in testimony ahead of a trial that started this week that State officials tried to get the Mafia to halt their terror campaign which continued with bombings that killed 10 and damaged artistic and religious sites in Rome, Florence and Milan. Former interior minister Nicola Mancino, one of two former ministers on trial alongside ex-Mafia bosses already convicted of Falcone and Borsellino's murders, is charged with giving false testimony. As well as being a witness, Ciancimino is facing charges in the same trial of helping Cosa Nostra and slandering former Italian police chief Gianni De Gennaro. The son of the Mob-linked mayor has claimed Italian officials received a series of 10 written demands from Toto 'The Beast' Riina, the Corleone-born boss of bosses who declared war on the State, but eventually rejected them. Ciancimino, whose reliability as a witness has been called into question, was arrested on suspicion of conspiring with others to dodge VAT on metal sales to the tune of 30 million euros. The judge who issued the warrant turned down a prosecutor's bid to add a further charge of mafia conspiracy for allegedly helping the Calabrian 'Ndrangheta mafia boost their drug trade through the largest container port in the Mediterranean, at Gioia Tauro in southern Calabria.