Russian convicts recruited to fight in Ukraine were warned they'd be shot if they deserted. One who did was returned to Russia — and was killed with a sledgehammer instead.

• Convicts and mercenaries have been recruited to help fight Russia's war in Ukraine.
• One convict recruited to the Wagner group deserted and turned himself in to Ukrainian forces.

Since Russia invaded Ukraine in February, its soldiers have complained about being unorganized, under-armed, and under-trained, with many expressing reluctance about entering into battles for which commanders did not prepare them.

A New York Times investigation published Saturday recounting Russia's numerous blunders during the war revealed additional details about two specific types of soldiers: convicted criminals and mercenaries. Wagner, a notorious mercenary group led by Yevgeny Prigozhin, an ally of Russian President Vladimir Putin, recruited many of those men.

Prigozhin, a Russian businessman and restaurateur, is also known as "Putin's chef," as his catering company has received government contracts worth several billion dollars. After years of denials, in September he identified himself as the founder of Wagner, which was formed in 2014.

Wagner is not under the control of the Russian military as mercenaries are technically illegal in Russia, but the group has come to be seen as the Kremlin's private army. They've been on the front lines in Ukraine fighting on behalf of Putin and Russia. To build up his forces, Prigozhin went to prisons and penal colonies to recruit more soldiers after Russian troops suffered major losses.

In August, he visited a prison near Moscow and recruited 55-year-old Yevgeny Nuzhin, who was serving 20 years on a murder conviction, according to the Times. In one video that captured Prigozhin's recruiting process, he told inmates they would be pardoned if they agreed to fight — and warned that if they joined and then deserted, they'd be shot.

Nuzhin enlisted, but after two days of recovering dead bodies, fled and turned himself in to Ukrainian forces. In an interview with the Times that occurred while he was a prisoner of war in Ukraine, Nuzhin said: "What good has Putin done in the time that he has been in power? Has he done anything good?"

"I think this war is Putin's grave," he added.

But soon Nuzhin would be dead.

Though the Times did not initially publish their interview with Nuzhin, he had also spoken to Ukrainian media, which published his name. During the interviews, he said he joined the Wagner group to leave prison and wanted to join Ukrainian forces and fight with them, The Guardian reported in November.

He was eventually returned to Russian forces in a prisoner swap, and shortly after appeared in a video shared by a Telegram account that has been linked to Wagner. The video showed Nuzhin lying down, with a man in camouflage standing over him, several outlets reported. "I woke up in this basement, where I was told that I will be judged," he said, according to the Times.

The man then strikes Nuzhin's head with a sledgehammer.

Prigozhin later expressed support for the murder on Telegram: "Nuzhin betrayed his people, betrayed his comrades, betrayed them consciously."

Family members of Nuzhin in November said they were "horrified" over the video after it was published. Nuzhin's son told The Guardian: "Our whole family was in tears watching the video … he was murdered like an animal."

The Times reported that when asked about the video by journalists, Dmitry S. Peskov, a spokesperson for Putin, said only: "It's not our business."