Khodorkovsky’s case should be fully investigated within a timeframe of two months, said top deputy prosecutor General Vladimir Kolesnikov on Wednesday.
Russia’s richest man was arrested on his private plane during a stopover in Siberia on 25 October and flown to Moscow to be detained on seven counts, ranging from fraud to tax evasion and embezzlement.
“If there is a great deal of work, we can extend his detention to 12 months, and if it turns out to be really overwhelming, up to two years," Kolesnikov told the Interfax news agency.
A Moscow court on Tuesday rejected Khodorkovsky's request for bail in a closed-door hearing in which the former chief executive of the Yukos oil company gave testimony via video link from his prison cell.
With a fortune estimated at $8 billion (seven billion euros), Khodorkovsky has been ordered to be kept behind bars until 30 December awaiting trial on seven charges that can land him in jail for up to 10 years. He could also have his assets confiscated.
His lawyers argue that the arrest was politically motivated since Khodorkovsky openly supported parties running against President Vladimir Putin's forces in parliamentary elections due 7 December.