Former senior secret service officials have alleged that he illegally took 3 million lire ( pounds 1,200) a month from the service's secret slush fund in addition to his normal salary, and that he took part - supposedly with Mr Mancino and the current President of Italy, Oscar Luigi Scalfaro - in meetings to agree on a cover-up story.
His resignation was rejected by Mr Mancino who, however, is in a precarious position himself. Comments by the Rome public prosecutor, Vittorio Mele, indicated that the magistrates will soon decide - possibly even today - whether the minister too, like two of his predecessors, should be investigated. If so, his case will be sent to the special Ministers' Tribunal, which deals with charges against cabinet ministers.
It was the second flare-up of the secret services scandal, which last year threatened to engulf President Scalfaro, who was also an interior minister and who now plays a key role in ensuring a smooth and constitutional transition from Italy's corruption and scandal- wrecked First Republic to its Second.
The former officials, accused of helping themselves to huge sums from the service's slush funds, have retaliated by charging that former ministers, including Mr Scalfaro, took illegal payments too. (One official was found recently to have 18 bn lire, or pounds 7.2m, in his bank account. He claimed the money was bonuses for special work he had done.)
The flare-up came only a few days before the President is expected to dissolve Parliament and call fresh elections. The timing strengthened suspicions that the allegations are designed to cause a constitutional crisis and prevent the elections, which will doubtless deal the coup de grace to the old political class, which clearly connived at corruption, and worse, in the services.
La Stampa, like other newspapers, called on the President not to be deterred. 'We are all convinced that the best way out of the morass of blackmail, calumny and destabilising plots into which we have fallen - and one which cannot be delayed - is the immediate dissolution of Parliament and fresh election,' it said in an editorial.
The government faces a no-confidence debate and vote in Parliament this week whose aim, at least originally, was to prolong the life of this parliament by replacing the present transitional government with another one. But Italian newspapers are reporting that Mr Scalfaro is determined to call elections.
Meanwhile the Prime Minister, Carlo Azeglio Ciampi, has publicly reaffirmed the government's support for Mr Scalfaro. Before leaving for the Nato summit in Brussels he sent him a letter expressing 'gratitude for all you are doing for the renewal of the country' and condemning the 'ever-meaner and more shameful attempt to involve your person in affairs about which the judiciary is seeking to establish the truth'.
Mr Parisi, who denied taking 'even a centime' that was not legally owing to him, warned at the weekend that a 'Mafia-type plot' was afoot to intimidate the President and weaken his position.Reuse content