“I AM Roman Sergeyevich Zabolotny, born in 1979, and I have been taken prisoner,” says a Russian-speaking man in a video released last month by the jihadists of Islamic State (IS). A second soldier, his right eye swollen shut, sits silently in grey robes. Both were reportedly captured during a battle near Deir ez-Zor, a city in Syria’s east and the site of a recent offensive by Russian and Syrian government forces. Yet the Russian defence ministry denied that any of its soldiers had gone missing. Friends and relatives told Russian media that the men had gone to Syria not with the Russian army, but as part of a shadowy mercenary force known as “Wagner”.

The group has come to play a key role in Russian operations in Syria. Though Russian law officially bans private military companies (PMCs), a St Petersburg-based independent news site, Fontanka.ru, reported in late 2015 that ex-soldiers were being recruited to serve in Wagner by a former special-forces officer, Dmitry Utkin. Numbering as many as 2,500 men, the group is believed to have figured heavily in operations around Palmyra in 2016, serving as “shock troops” alongside the Syrian army, says Mark Galeotti, an expert on Russian security at the Institute of International Relations in Prague. Though the Russian army has not acknowledged Wagner’s existence, Mr Utkin was photographed late last year alongside President Vladimir Putin at a Kremlin reception for military officers in honour of Day of Heroes of the Fatherland. This summer America added him to its list of officials sanctioned for involvement in the Ukraine conflict of 2014, where the group is said to have got its start.

When Russia launched its intervention in Syria in September 2015, the government spoke of a short air operation. Boots on the ground were seen as taboo, especially to a population still haunted by memories of the costly Soviet war in Afghanistan. (Nearly half the population would now like to see the Syrian operation wrapped up.) But having a nominally independent cadre of fighters to deploy as ground forces gives the Russian army plausible deniability. “They serve to solve a concrete problem: have no casualties,” says Alexander Golts, a military analyst. Officially Russia’s armed forces have in fact reported some 41 deaths in Syria, including a general killed in shelling near Deir ez-Zor in September while commanding Syria’s Fifth Corps of volunteers. However, investigative journalists and bloggers reckon scores more Wagner-linked mercenaries have died in combat. On the ground, the force functions as a “pseudo-private” military company, taking direction from the Russian army, says Alexander Khramchikhin, deputy director of the Institute for Political and Military Analysis.

The model was first tested in the war in eastern Ukraine, where a patchwork of forces operated with differing degrees of distance from the Russian government. Alongside local separatists and regular Russian army units were groups of Russian volunteers and mercenaries, among them Mr Utkin and an early iteration of the Wagner force. “The rumours are that they fought, and fought well,” says one former senior separatist commander, with a sly smile. As fighting slowed in 2015, mercenaries and volunteers returned home or sought employment elsewhere. It is no secret that many of them have since left for Syria, says another former separatist leader.

The emergence of such groups revived talk in Russia of legalising Russian PMCs to create companies in the vein of American security contractors such as Academi (formerly called Blackwater). Mr Putin expressed tentative support for that idea back in 2011, calling it “a way of implementing national interests without the direct involvement of the state”. In late 2014 Gennady Nosovko, a lawmaker with the Just Russia party, submitted a bill that would have laid the legal groundwork, only to see Russia’s powerful Security Council snuff it out. Resistance was also strong from within the military and security services, which worried about losing their monopoly of violence. Other specialists, Mr Nosovko says, worried that powerful businessmen would ultimately seek to control their own private armies, with dreadful implications.

For now, the Wagnerians still operate in a grey zone. Fontanka.ru recently reported that their role has expanded to include seizing oil wells held by IS for a newly-formed Russian company, Evro Polis. As for the two captives, their fates are probably sealed, says an MP from the home region of one of them. “There’s a 99% chance that Roman and the second prisoner are no longer among the living.”