Russian President Vladimir Putin insists — insists! — that he is definitely not invading Ukraine. The US and others say that, in fact, Russia has been sending military combat units into eastern Ukraine since August, where they are supporting pro-Russia rebels in the war against Ukraine government forces.

But Vice News's Simon Ostrovsky, in a new report, tracks the social media postings of a Russian soldier to prove that Putin is lying and that Russia is in fact at war in Ukraine. In the above video, Ostrovsky retraces the steps of a Russian soldier named Bato Dambaev, who posted highly incriminating selfies all along his journey from his home in Russia's far east to a Russian military encampment near the Ukrainian border to a checkpoint within eastern Ukraine along the front lines of the war.

Ostrovsky's investigation is based in large part on a recent Atlantic Council report that documents Russian soldiers' social media accounts, satellite photos, and many other pieces of open-source evidence to demonstrate that Russia's military is engaged in an undeclared war against Ukraine.

Here's Ostrovsky reproducing a photo that Dambaev posted of himself on an account on VK, a Facebook-like Russian social media account. Dambaev is normally based in a far-eastern part of Russia near Mongolia. But this photo, Ostrovsky found, was taken in a part of Russia much closer to Ukraine, near a massive Russian military encampment that Russia says is for "exercises" but analysts believe is in fact the staging ground for the invasion of Ukraine.

Another photo, showing Dambaev inside a Russian tank, was geotagged, apparently from within the Russian military encampment on the border.

The most damning photo, tagged in February, showed Dambaev in uniform in what turned out to be eastern Ukraine — near the town of Debaltseve, where pro-Russia rebels won a major victory against Ukrainian forces around that same time.

The implications of this are pretty clear: Russian military units had been sent into Debaltseve in February to fight alongside rebels there.

There is other evidence corroborating this. Back in March, the BBC interviewed a Ukraine-based rebel fighter who said the rebels had only won the battle in Debaltseve with helped from a Russian military tank unit sent from the far-eastern region of Buryatia. "Thanks to their help and their armor we managed to take Debaltseve," he said.

Bato Dambaev is from Buryatia, and his photos show him training with a tank unit there. That would appear to be his unit that, sent from thousands of miles away and funneled secretly into eastern Ukraine, won the battle of Debaltseve.

The rebel interviewed by the BBC also said that "all operations, especially large-scale ones, are led by Russian officers, by Russian generals" — suggesting that Russia's military is not just helping the rebels but leading them.

You will also notice, in the photo from Debaltseve, that Dambaev is wearing a white armband and legband, but there is no longer a Russian flag on his uniform. This appears to be part of Russia's effort to hide its invasion. But that's getting harder to do, for many reasons. One of them is that soldiers like Dambaev, who are members of Russia's Asian ethnic minorities, really stick out in faraway eastern Ukraine. Ostrovsky interviews eastern Ukrainians in a village near the front lines; they recall such Asian-looking soldiers coming through, and remark that they were more polite and better-trained than the volunteer rebels.

At the end of the video, Ostrovsky follows Dambaev back to his hometown in Buryatia, in Russia near the border with Mongolia, where he has returned. He meets Dambaev's wife, but is only able to confront Dambaev himself over the phone. The Russian soldier denies that he was in Ukraine and, in a moment of obvious panic, denies that he knows anything about the photos — though he himself had taken the photos and posted them to his VK account.

Interestingly, Dambaev's VK page lists him as active-duty in the Russian military through 2016. Some earlier reports had suggested that Russia was suppressing the truth about its Ukraine invasion by forcing soldiers to resign from the military before "volunteering" to fight with the rebels there. Now, it appears, they are no longer bothering.