By Wladimiro Pantaleone
PALERMO, Italy, July 18 (Reuters) - Magistrates have launched a formal investigation against an Italian senator on suspicion that he attempted to blackmail his longtime patron, former Prime Minister Silvio Berlusconi, over alleged mafia links, judicial officials said on Wednesday.
The latest judicial affair to involve the 75-year-old media tycoon came days after officials in his People of Freedom party said he would run as centre-right candidate for premier in next year's general election.
Berlusconi was summoned to a meeting on the case by Palermo prosecutors on Monday but declined to attend on the grounds that he had official business said the officials, who spoke on condition of anonymity.
The case is part of a wider investigation into alleged links between organised crime and state officials in the early 1990s, a bloody period which saw the murders of the two leading anti-mafia magistrates, Giovanni Falcone and Paolo Borsellino.
Magistrates want to find out if Dell'Utri, one of Berlusconi's closest associates who is separately appealing a conviction for mafia association, was paid not to reveal details of alleged connections between Berlusconi and organised crime figures.
Dell'Utri, a former manager in Berlusconi's Fininvest business empire, said he knew nothing of the accusation and had only learned of the case from the press. But he strongly denied blackmailing his former boss.
"Now it's extortion. They're just missing accusing me of pedophilia and I'd have the lot," he told reporters. "I have certainly never blackmailed anyone, least of all my friend Silvio."
Berlusconi, one of Italy's richest businessmen as well as its dominant political figure over the past 20 years, has always denied any connection with organised crime and repeatedly accused what he calls politically motivated leftist magistrates of trying to destroy him in a long string of court cases.
According to the daily La Repubblica, magistrates are focusing on the sale of a villa on Lake Como, which Berlusconi is reported to have acquired from Dell'Utri last year for more than 20 million euros, as well as other payments to the Senator.
In an interview with the daily Libero on June 28, Palermo chief prosecutor Antonio Ingroia said he believed Berlusconi had been subject to extortion by the mafia.
"Dell'Utri was the one who carried this threat and that's why he is being investigated," he said.
(Reporting By Wladimiro Pantaleone; writing by James Mackenzie; editing by Barry Moody)