In a video released earlier this month, Zemlyanka, bearded and dressed in camouflage, slit the throat of a man who, minutes earlier, had confirmed in Russian that he was a spy sent by the FSB, Russia's state security organisation that came after the KGB.
Chechnya’s pro-Moscow leader, Ramzan Kadyrov, also confirmed later that the beheaded man was a Russian spy dispatched to ISIL-controlled territory.
He also said he lived in Chechnya, Russia’s mostly Muslim province which fought two separatist wars against Moscow and is part of the Caucasus region beset by violence among armed groups, federal forces and local clans.
Meanwhile, a Russian court charged Zemlyanka in absentia for joining an illegal armed group outside the country, the Interfax news agency reported. 
Zemlyanka grew up in the Siberian town of Noyabrsk and joined ISIL in 2013, according to Russian media reports which added that he convinced two friends to join the group.
Thousands of Russians are believed to have joined ISIL, most of them from the Caucasus.
“He looks like a Slav, not someone from the Caucasus, and this is perceived as an additional threat,” Sergei Markov, a Moscow-based political analyst, told Al Jazeera.
Russians are part of the Eastern Slavic ethnic group, and Markov added that ISIL was "massively recruiting Slavs", pledging to send them back to Russia to organise terrorist attacks.
In the past two years, many armed groups in the Caucasus have pledged allegiance to ISIL, and thousands of young men have left Russia to join the group
Source: Al Jazeera