All the defendants are residents of the Russian republics of Ingushetia, Chechnya, and Kabardino-Balkaria.
On 28 July, a jury court in Nazran convicted them of participating in coordinated militant raids that targeted Ingushetia's law enforcement agencies.
The attacks, which took place on 21 June 2004, left 80 people dead and 100 wounded.
Ingushetia's acting Interior Minister Abukar Kostoev and Nazran's Prosecutor-General Mukharbek Buzurtanov were among the victims.
Russian officials have said the assailants were linked to separatist fighters in neighboring Chechnya.
For RFE/RL's complete coverage of events in Russia's North Caucasus, see News And Features On The North Caucasus.