Russian investigators on Tuesday said they were searching the Moscow offices of the world\'s largest aluminium producer Rusal as part of a probe into alleged tax violations which the company dismissed as groundless. \"Items and documents (obtained as a) result of the searches... will be made part of the material of the criminal probe,\" the powerful Investigative Committee\'s Moscow branch said in a statement. Rusal, owned by Russian billionaire Oleg Deripaska, said in a statement that the searches in its office were linked to a tax investigation against a subsidiary which it said had no foundation. The investigators\' actions \"are connected to the groundless claims of the tax authorities and the Investigative Committee against Rusal Folga (a Rusal subsidiary) and its management,\" it said in a statement. Rusal said the claims by tax authorities were based on a court decision which has not yet gone into effect. The Investigative Committee earlier this month launched a probe into large scale tax evasion by the head of Rusal Folga, an aluminium foil subsidiary of the Hong-Kong-traded giant. The subsidiary\'s head Igor Kasyanov is suspected of evading taxes in the amount of over 200 million rubles ($6.5 million) according to the investigators, who said in a statement that Kasyanov doctored the subsidiary\'s books between 2008 and 2009 to record services of a \"fictitious company\". The potential tax evasion charge against Kasyanov carries up to six years in prison. Russia\'s tax authorities last year demanded that Rusal Folga pay over 289 million rubles of taxes and fines, however the firm filed a lawsuit against the claims in the arbitration court. The court ruled in favour of the tax inspection on January 23. According to the publicly-available decision, the tax authorities are disputing transactions between Rusal Folga and a small firm from which it purchased paper, paint, and other materials. The firm was found by tax inspectors to be \"fictitious\". Rusal said in a statement that \"it cannot be held responsible\" for actions of its suppliers, vowing to appeal the court decision. Rusal Folga is located in the same office as Rusal\'s Moscow headquarters. News agency RIA Novosti reported from the scene that nobody was being allowed inside the building in central Moscow with special forces troops stationed at the reception. Investigative Committee spokesman Vladimir Markin said on his Twitter account that the investigators are not searching Rusal\'s main office but the office of Rusal Folga. Rusal, which listed in Hong Kong in January 2010, in August posted a net interim profit of $37 million, down sharply from $779 million a year earlier.