An underground network of Russians says it’s helped Ukraine hit nine refineries. Almost everything we know about the group comes from one man — a former Gazprom executive.

The BBC Russian Service interviewed Igor Volobuev, a former senior executive at Gazprom and Gazprombank who now fights for Ukraine. Born in Ukraine, Volobuev spent more than 30 years in Russia but went home as soon as the full-scale war began. He once handled public relations and press outreach at Gazprom companies; today he is a drone operator in the Ukrainian army. Since May 2026, he has also served as the “face” of Chernaya Iskra, or Black Spark — an underground movement that allegedly ope...