The Klaipeda regional court's ruling, which comes after seven years of investigation and trial, is likely to be appealed to a higher court.
Zigmas Pocius, the judge who heard the case in Klaipeda, told BNS that prison sentences (not suspended) had been handed down to Naftos Grupė's owners and top executives, Artūras Urbutis and his brother Antanas Urbutis, as well as to Ričardas Milvydas, a former commercial director of Klaipėdos Nafta.
Another three people, including Klaipedos Nafta's former CEO Jurgis Aušra, have been sentenced to suspended prison sentences.
"Look at what amounts of money were involved and how dangerous the crime was. There were no mitigating circumstances," the judge told BNS.
A four-year-long investigation by law-enforcement bodies established that Naftos Grupė had enjoyed exceptional terms from Klaipėdos Nafta between 2005 and 2010 under a contract obtained by Artūras Urbutis, Naftos Grupė's sole shareholder, by using his father-in-law's connections with Aušra. The contract was loss-making for the state.