MOSCOW, March 23. /TASS/. Russian investigators intend to prove the illegality of acquisition by the now defunct Russia's Yukos oil company’s shareholders, including Mikhail Khodorkovsky and Leonid Nevzlin, of the company’s controlling stake.

"During the investigation of the "main Yukos case" searches were conducted at the places of a number of former top managers of the company the results of which will make it possible to prove that in 1995-1996 a group of persons led by Khodorkovsky through companies controlled by them purchased 78% of shares of the Yukos oil company, including 45% of federally-owned shares," an informed source told TASS.

According to him, Khodorkovsky later sold 60% of the Yukos shares to foreign companies controlled by him.

"Documents seized during the searches will be also presented to the international court as the evidence of illegality of bringing claims by foreign companies against Russia with The Hague arbitration court," the source said, adding that the pre-investigation check was still underway.

The so-called main Yukos case was opened in March 2003 over facts of inflicting damage on the state.

Last December, the Russian Investigative Committee said that its main investigation department was probing a criminal case against the former main shareholders and managers of Yukos over the theft and sale of oil from Yukos subsidiaries by them, as well as money laundering (Article 160, part 3 and Article 174.1 part 3 of the Russian Criminal Code).

According to Investigative Committee spokesman Vladimir Markin, in connection with international proceedings initiated by the foreign companies Hulley Enterprises Limited, Yukos Universal Limited, Veteran Petroleum Limited with a view to recovering more than $50 billion from Russia, the investigation is also checking information presented by the plaintiffs to international and foreign courts for legality and legitimacy of the purchase of Yukos shares and their following disposal.

Yukos oil giant was accused of tax crimes and declared bankrupt by a Russian court ruling in 2006 while its assets were sold at auctions during the liquidation procedure.

Yukos former head Khodorkovsky and his business partner Platon Lebedev were found guilty of embezzlement and tax evasion in May 2005 and sentenced to nine years in prison.

While serving their prison term, both Khodorkovsky and Lebedev were found guilty of embezzlement and money laundering in a second criminal case in December 2010 and sentenced to 14 years in prison, with account taken of the jail term they had served.

Khodorkovsky was pardoned by Russian President Vladimir Putin and left the prison in December 2013. Lebedev was released from jail in early 2014.