Ukrainians, often teenagers, were offered money via Telegram to carry out the attacks by “curators” who used a mixture of enticements and blackmail to snare their recruits.

The perpetrators then had to make a video of the fire on their phones, and send the recording as proof the deed had been done. The videos would invariably find their way on to Russia-friendly Telegram channels, as supposed evidence of discontent inside Ukraine, stoking real social tensions over issues such as conscription that have flared during Russia’s war on the country.