“Yesterday, criminal investigation officers from the city’s police detained a chief special communications technician from a unit of the Russian Internal Troops on suspicion of committing a crime,” the source said. He added that an investigation is in progress.

A homemade bomb consisting of a metal container with 2 kg of a TNT mixture, smoke powder and aluminium powder, as well as a homemade detonator, two batteries and electrical wires was found by the front door of a 10-storey apartment block in Chelyabinsk on Jan. 5. The building’s residents were evacuated while the bomb was defused.