Russia and South Ossetia today denied being involved in the 1 February attack.
Merabishvili identified the man as being Anatolii Zaitsev of the Russian Army's Main Intelligence Directorate.
Merabishvili said three suspects arrested in the past few days had admitted to being part of the group, which allegedly operates from Georgia's breakaway region of South Ossetia. He also said another six suspects are being looked for.
Also addressing reporters in Gori, the head of the Georgian parliament's defense and security committee, Givi Targamadze, accused Russia of carrying out sabotage operations in Georgia.
"It is very unfortunate that our suspicions that Russia could be directly involved in our internal conflict [with South Ossetia] have proved founded," Targamadze said. "[The Russians] are directly training groups of saboteurs. We'd said in the past that we had information. These groups are quite large, numbering -- according to our information -- about 120 people. In addition, there are quite a lot of [Russian] agents on Georgian territory."
In Tbilisi today, Russian Embassy spokesman Yevgenii Ivanov denied any Russian involvement in the Gori bombing and other attacks.
South Ossetia's authorities issued a similar denial, describing the Georgian charges as a "provocation."
(imedi tv/ITAR-TASS/RIA-Novosti/Civil Georgia/Novosti-Gruziya)
Georgian President Calls Bomb 'Political Terrorism'