The seven victims -- including a regional lawmaker -- were all shareholders in a local factory. Their charred bodies were discovered in a mine shaft nearly one month after they disappeared in October 2004.
Among the 16 defendants in the case is Ali Kaitov, a local magnate and the former son-in-law of the republic's president.
Kaitov and another seven defendants are accused of organizing the murder. The rest of the defendants are accused of withholding information from the police.
The disappearances of the businessmen sparked a crisis in the region with hundreds of relatives demanding the resignation of the local government.
The trial began some six months ago.