A Moscow court on Thursday convicted two Chechen natives linked to Islamist militants of kidnapping the son of Rosneft vice president Mikhail Stavsky.
Investigators said the suspects kidnapped the teenager for ransom in April 2009 in order to finance North Caucasus insurgents.
Magomed Gorchkhanov, 38, was sentenced to 14 years in a maximum-security prison, and Zarema Datayeva, 34, to six years in a regular prison, a spokeswoman for the Gagarinsky District Court told The Moscow Times. They were also fined a combined 1 million rubles ($32,800).
Gorchkhanov pleaded guilty, saying he had needed the money, but Datayeva denied involvement, RIA-Novosti reported. Both vowed to appeal.
“Both convicts are angry because they believe the sentence is too harsh. They plan to appeal,” the court spokeswoman said.
Also implicated in the case were Andrei Karpov, a former police officer who converted to Islam, and Datayeva's common-law husband Vitaly Chernobrovkin, both killed by law enforcement officers during a shootout with suspected insurgents in the North Caucasus in August 2009.
A fifth suspect, Alexander Yashin, is facing a separate trial after being wounded and detained in an unrelated fight with insurgents in Ingushetia, Interfax reported.
The son of Stavsky, also named Mikhail, was abducted in front of his oil institute in Moscow and imprisoned in a house in the Moscow region for two months while the kidnappers demanded an unspecified sum for his release. He was 17 at the time.
In June 2009, Datayeva was arrested, which prompted the kidnappers to release the teenager under murky circumstances. Gorchkhanov was detained in January.
Investigators earlier said Gorchkhanov and Datayeva had acted on behalf of the insurgents' chief ideologist, Alexander Tikhomirov, also known as Said Buryatsky, who was killed in Ingushetia in March. But those allegations were not mentioned by the court spokeswoman or in news reports about the court's verdict.
The younger Mikhail Stavsky, who currently lives in London, did not attend the trial. The father has said his son was still recovering psychologically from the ordeal.