In 2014, there were explosions at two Czech arms depots. There were two explosions in Bulgaria, as well. One took place at the military factory in Sopot. They are the work of the same people from Department 29155 of the Russian main intelligence directorate, known as GRU. This is what Hristo Grozev of the investigative journalism website Bellingcat has told the "Horizont" program of the Bulgarian National Radio.

"It's very difficult not to see the link between this group of GRU officers and the explosions." At least two of them have received the Hero of the Russian Federation award since the operation, according to a Belingcat investigation.

Grozev links the actions to the war in Ukraine. Certain type of anti-tank ammunition was then exported to Kiev. The ammunition "had a key effect on the balance in the war at that time," analyzes show.