(ANSA)- Rome, August 29 - Italy's supreme Cassation Court on Thursday filed its guilty verdict and the motivations behind its August 1 ruling against ex-premier Silvio Berlusconi for tax fraud at his Mediaset media empire. Justices usually take months before issuing their explanations behind a ruling. Lawmakers and politicians from the three-time premier's People of Freedom Party (PdL) accused justices of political bias and rushing proceedings early last month when the Cassation quickly scheduled his final appeals trial to start July 30. Justices said the quick turnaround was to make sure the case did not time out under the statute of limitations, something that has happened multiple times in Berlusconi's past legal entanglements. This is Berlusconi's first-ever binding criminal conviction. He was sentenced to four years in prison, which was commuted to one year of community service or house arrest because of an amnesty. The Senate is voting next month on ratifying a subsequent ban from office that would strip him of his seat from the upper house.