The jury said investigators were able to prove the guilt of Igor Gubkin, a member of the so-called Revolutionary Military Council, but said he deserved leniency in the case.
It acquitted Gubkin of charges he organized a revolutionary council and attempted a coup d'etat, but ruled he was guilty of apartment fraud.
Lawyer Dmitry Agranovsky said the court stopped criminal proceedings against Gubkin on charges of mining a gas distribution plant in the Moscow region's city of Lyubertsy in 1997 for lack of proof.
"Gubkin has been in custody since August 2, 1997, but the crime was committed in November of that year," he said.
Agranovsky said the defense and prosecution would discuss the verdict Wednesday, following which the court will withdraw to consider the sentence.
Gubkin pleaded not guilty in a closed court.