"All obtained objective data makes it possible to completely exclude the version of a blast on board the aircraft," Petrenko said.
On December 25, 2016, a Russian Defense Ministry Tu-154 plane heading from Moscow to Syria crashed in the Black Sea shortly after refueling and taking off from Russia's southern city of Adler, near Sochi.
None of the 92 people, including eight crew members: 64 musicians of the Alexandrov Ensemble, nine reporters, head of the Spravedlivaya Pomoshch (Fair Aid) charity Elizaveta Glinka, and two federal civil servants, survived the disaster.
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Meanwhile, Sochi's authorities held a memorial service for the crash victims, during which several hundred city residents maintained a moment of silence, lighting candles and releasing flowers into the sea.
