Russian mercenaries loyal to Vladimir Putin were driven to an almost certain death after they were captured by ISIS fighters.
A father-of-two, Roman Zabolotny, 39, and his comrade, Grigory Tsurkanu, 38, are thought to have been killed in a town square in front of cheering crowds after this clip was taken.
They refused to reject their Orthodox Christian faith to become ISIS -backing Muslims, according to one version of events.
The pair were held last week in intense fighting around the eastern city of Deir Ezzor, an ISIS stronghold in Syria .
Wounded, the video shows them being moved as war trophies in a jihadist vehicle, their legs tethered by rope and hands tied behind their backs.
Tsurkanu appears to be in pain. They have no common language, the ISIS terrorists speak no Russian, but keep trying to ascertain if the two are troops sent by Putin, as they believe.
At one point they try French, to no avail. The jihadists even suspect them of being Iranian.
Yet they were Russian - members of a secret and deniable mercenary force deployed in Syria by the Kremlin, not official troops on the payroll of the Defence Ministry.
Perhaps sensing execution, Zabolotny seeks to communicate with his captors and at one point says: "I have information about weapons."
The men later appeared in an ISIS propaganda video which claimed inaccurately that the men were serving Russian soldiers.
There are suspicions a third Russian was also grabbed by jihadists but no information has been released about him.
Senior Russian MP Viktor Vodolatsky said: "It is very sad but 99 per cent Roman Zabolotny is not alive, nor is the second prisoner.
"Before filming that video they were given a statement which they had to read.
"In this text they would reject their Orthodox religion, reject their motherland, become Muslim and join ISIS.
"They stayed loyal to the Orthodox faith and their Motherland until the very end, and this is what they were killed by those gangsters for."
There has been no official confirmation from the Russian authorities about their fate, but Vladimir Putin's government is coy speaking about such mercenary forces in Syria and other hot spots, even though experts say they work closely with the armed forces.
A local MP in Rostov-on-Don, Zabolotny's home city, also confirmed the pair had been "executed", saying it happened the day after the video was made.
"Unfortunately, this is true," said Anatoly Kotlyarov.
"Information was received that they were executed" in a town square.