Flames lick around the edges of Omar's passport. It's burning well, an unseen woman says in Russian in the video.

Omar, a 26-year-old Syrian construction worker, had been deployed for about nine months on the front line of Russia's war in Ukraine when the clip arrived on his phone.

He knew the woman's voice. It was Polina Alexandrovna Azarnykh, who he says had helped him sign up to fight for Russia, promising lucrative work and Russian citizenship. But now she was angry.

In a series of voice notes from Ukraine, Omar, speaking under a pseudonym for his safety, describes how he ended up trapped and terrified in the war zone.

He says Azarnykh had promised that if he paid her $3,000 (£2,227), she would ensure he stayed in a non-combat role. But, he says, he was sent into battle with just 10 days of training, so he refused to pay and she eventually responded by burning his passport.

He says he tried refusing to take part in a mission, but his commanders threatened to kill or jail him.

We were tricked… this woman is a con artist and a liar, says Omar.

A BBC Eye investigation has followed how Azarnykh, a 40-year-old former teacher, uses a Telegram channel to lure young men, often from poor countries, into joining Russia's military.

The former teacher's smiling video messages and upbeat posts offer one-year contracts for military service. The BBC World Service has identified nearly 500 cases where she provided documents that allowed men to enter Russia to join the military.

Her posts often mention recruitment for an elite international battalion and make clear that people in Russia illegally can also enlist.

But recruits and their relatives have told the BBC that she misled men into believing they would avoid combat and failed to clarify that they could not leave after a year, while threatening those who challenged her.

Twelve families told us of young men they say were recruited by her, who are now dead or missing.

Domestically, Russia has expanded conscription, recruited prisoners, and offered increasingly generous sign-up bonuses to maintain its operations in Ukraine, despite substantial losses. Over one million soldiers have been killed or wounded since the full-scale invasion in 2022.

Azarnykh's Telegram channel has 21,000 subscribers. Her posts have frequently misled recruits regarding the nature and risks of military service. One recruit reported, A lot of injuries, a lot of explosions. If you don't die from the explosion, you'll die from the debris landing on you.

Ultimately, Azarnykh has emerged as a crucial link in Russia's recruitment strategy, exploiting vulnerable individuals under the guise of military service, leading many to tragic outcomes on the front lines of Ukraine.