CNN  — 

The chief of Russian paramilitary group Wagner told CNN on Thursday that he has handed the body of Nicholas Maimer, a retired US Army Special Forces soldier who was killed in the battle for Bakhmut, over to Ukraine.

Yevgeny Prigozhin, when asked by CNN if Wagner had returned the body of Retired Army Staff Sgt. Maimer as promised by Prigozhin last week, said in an audio recording: “Today at 15:00 hours we handed over the body of the American Nicholas Maimer to the Ukrainian side.”

Maimer was in a building in Bakhmut that collapsed after being hit by artillery fire, according to Retired Lt. Col. Perry Blackburn, founder of the non-profit AFGFree, with which Maimer was working in Ukraine.

Ukrainians who were with Maimer believed he was either trapped in the collapsed building or killed by a “barrage” of Russian artillery fire, Blackburn said. CNN cannot independently verify details of Maimer’s death.

In a video shared with CNN by Prigozhin’s press service, the Wagner boss is seen standing next to two coffins, one draped with an American flag and one with a Turkish flag, and says: “The American died in battle in the ‘nest’” – one of the last contested areas in west Bakhmut – and added that the second coffin contained the body of a Turkish citizen who was in Bakhmut with his female partner.

“They were found under the ruins of a building, or more accurately he and his documents. When the Ukrainians withdrew they blew up the building, and they died under the destroyed building. We weren’t able to get her out, but we got him out and will return to his motherland,” Prigozhin says of the Turkish citizens. CNN cannot independently verify the location in the video or the date it was filmed.

Ukraine’s Coordination Headquarters for the Treatment of Prisoners of War confirmed to CNN that Maimer’s body, along with the body of a Turkish citizen, had been returned to Ukraine on Thursday during a POW exchange. A video shared by the group showed a coffin covered with an American flag which matched the coffin seen in the video with Prigozhin.

CNN is unable to independently confirm that the coffin contains Maimer’s body. After his death last week, Prigozhin claimed to show the body of an American in a video posted on the Wagner Telegram group.

A pro-Kremlin military blogger, Alexander Simonov, introduces the video saying “we are advancing to the advanced positions of the PMC Wagner in the western regions of Artyomovsk,” the Russian name for Bakhmut. Prigozhin is shown inspecting a body, and what he claims are US identification documents.

Prigozhin says, “So we will hand him over to the United States of America, we’ll put him in a coffin, cover him with the American flag with respect because he did not die in his bed as a grandpa but he died at war and most likely a worthy [death], right?”

CNN cannot verify the authenticity of what is shown in the video, and Maimer’s family did not return CNN’s request for comment. However, Maimer’s uncle Paul confirmed to the Idaho Statesman that the body in the video was that of Maimer.

CNN’s Rob Picheta, Josh Pennington, Sandi Sidhu, Jennifer Hansler, Haley Britzky and Alex Marquardt contributed reporting