Italy's Supreme Court has issued a text explanation from judges on why they upheld the former Prime Minister Silvio Berlusconi's sentence for tax fraud.
The 1 August ruling confirmed a one-year prison term and ban on political office for the billionaire senator. Neither measure has yet been enforced.
Berlusconi argued he did not know prices of film distribution rights were pushed up to reduce tax on their sale.
He faces possible expulsion from parliament over the verdict.
The move could have implications for Italy's government, as he leads a centre-right party which is a partner in the coalition.
Judges said Berlusconi initiated the scheme and knew perfectly well how it worked.
He was the "mind behind the mechanism," they said.
The former PM colluded with the management to allow the continued rising costs of his Mediaset business empire for the purpose of tax evasion, the judges' document said.
He operated a "game of mirrors" to artificially inflate the price of TV rights, the judges said, according to the Ansa news agency.
"This defendant, this businessman, would have had to have been completely clueless" not to realise the tax fraud scheme that was in place, they said.
A court in October is expected to decide whether he will have to serve his one-year sentence as community service or under house arrest, the Associated Press news agency reports.
Berlusconi's lawyers are challenging a series of convictions. He has complained he is the victim of a vendetta led by left-wing magistrates from his home city, Milan.