This month's dramatic Ukrainian advance north of Kharkiv drove Russian forces back across the border, and uncovered evidence of torture under their occupation.
Ukraine's military focus has shifted east, but police and prosecutors have taken over the border community of Kozacha Lopan, and have launched an investigation.
The small town's police station was used during the occupation as a base by a local pro-Russian militia, and alleged torture victims have come forward to testify.
"The people who worked as so-called 'policemen' in the so-called 'People's Police' are known," district war crimes prosecutor Kateryna Shevtsova told AFP.
"Measures for bringing them to justice will be taken in the coming days. Most of them were locals," she said, at the municipal administration, surrounded by armed police.
Ukraine's President Volodymyr Zelenskyy has denounced the Kremlin's forces as "murderers" and "torturers" — while Moscow has dismissed atrocity claims as "lies".
District war crimes prosecutor Kateryna Shevtsova is leading the investigation into torture claims in the in the liberated Ukrainian town of Kozacha Lopan in the Kharkiv region. Source: AFP / YASUYOSHI CHIBA
What are pro-Russian forces accused of doing?
"Olexander" — AFP agreed to conceal his real name and identity as he has relatives in Russian-occupied Crimea — said he was arrested on 22 March by gunmen in two SUVs.
His captors, he said, turned out to be militia from the so-called Luhansk People's Republic, a proxy force set up in 2014 with Moscow's backing in an eastern enclave of Ukraine.
As a veteran of Ukraine's "Anti-Terrorist Operation" — its war against the Luhansk and Donetsk pro-Russian forces — Olexander said he was a prime target for arrest.
Returning to the scene of his torment at the hands of his Russian captors, the 40-year-old lay down, twitching to show how he said he flailed and spasmed after Russian militia interrogators attached an electric cable to his penis.
Words spilled out of him as he recounted how he was frog-marched into this room, beaten, kicked, and given electric shocks.
So violently did he jerk with the cable on his genitals, he said, that his captors had to cushion his head from hitting the floor to keep him conscious for questioning.
"Olexander" says as a veteran of Ukraine's "Anti-Terrorist Operation", he was a prime target for arrest. Source: AFP / YASUYOSHI CHIBA
"I told them don't hit me, I have a hernia, but then they pulled down my pants," he said. "They called it 'electroshock therapy' when they hit me with the electricity."
"I felt like they were pouring molten metal into me, inside of me," he said.
Olexander was held in the railway station in the small town where he had lived all his life for around five days, then transferred to a larger prison in Hoptivka.
Eventually, on 17 April, his captors surprised him by letting him leave, he presumes because they needed space for new Ukrainian prisoners of war.
He made his way back to Kozacha Lopan and when the town was recaptured by Ukrainian forces this month, he contacted the Ukrainian police.
Kozacha Lopan is on a main rail line south across the international border from Russia to the Ukrainian city of Kharkiv and was one of the first towns to fall.
Today, the area is under the control of Ukrainian forces but is still tense.
The prosecutor is moving quickly with her investigation, convinced that she has all the evidence she needs to round up the suspects she accuses of working with the Russian occupation.
"We conducted an inspection of the basements, where, as we all know from the evidence, people were tortured," Ms Shevtsova said. "This is all confirmed."
Mass graves uncovered
On Saturday, Ukrainian emergency workers dug up more bodies from a wooded burial site in territory recently recaptured from Russian forces while townspeople looked for dead relatives.
Ukraine says hundreds are buried at the site discovered this week, including at least 17 Ukrainian servicemen found in a mass grave on Friday and others who may be civilians buried in individual graves marked with flimsy wooden crosses.
The causes of death have not yet been established, although residents say some of the graves near the town of Izium were of people who died in an airstrike.
Workers exhume bodies from graves in Izyum, Kharkiv region, northeastern Ukraine, on 16 September 2022. Source: Reuters / EPA
What did they find?
Ukrainian authorities have said at least one of the bodies had tied hands and rope marks on the neck.
Moscow has not commented on the discovery of the graves. It has regularly denied committing atrocities in the war or targeting civilians.
Reuters saw workers carefully exhume at least five graves with shovels while police experts and investigators documented the findings on camera and inspected the bodies on the sandy soil between trunks of pine trees.
Ukrainian servicemen stand near workers carrying bodies that were were unearthed from graves in Izium, Kharkiv region, northeastern Ukraine, on 16 September 2022. Source: AAP / EPA
"Exhumations are under way. Their identities are currently not known," said Roman Kasianenko, a regional prosecutor.
He said three bodies dug up on Friday had been identified.
Graves marked with numbers
Clutching a neatly written list of names and numbers, resident Volodymyr Kolesnyk stepped between graves looking for relatives he said were killed in an airstrike on an apartment building shortly before the town fell in April, as the invaders swept through the northeastern region of Kharkiv.
Mr Kolesnyk said he knew his relatives had been taken to the burial site and were in some of the graves marked with numbers but that he had not dared visit while the town was under occupation.
He paused before a cross marked with the number 199 and, after checking the list, carefully hung a small sign on it bearing the name of Yurii Yakovenko, his cousin.
Cross number 164, he said, was his cousin's wife. And 174 is the cousin's mother, Mr Kolesnyk's aunt.
The list was given to him by a local funeral company that dug the graves, he said.
"They buried the bodies in bags, without coffins, without anything. I was not allowed here at first. They [Russians] said it was mined and asked to wait. And there was a lot of them in the woods, so it was scary to come here," Mr Kolensk told Reuters.
Ukrainian President Volodymyr Zelenskyy on Saturday said officials have found evidence of torture on exhumed bodies, adding that around 10 torture sites have been found across the territory liberated this month.
How is it being reported in Russia?
The head of the Russia-installed administration that abandoned the northeastern area around Izium last week accused Ukrainians of staging atrocities.
"I have not heard anything about burials," Vitaly Ganchev told Rossiya-24 state television.
Moscow is facing fresh outrage from the West after the discovery of the mass grave.
But Mr Putin remained steadfast, saying his war against Russia's Western-leaning neighbour was proceeding according to plan.
"The plan is not subject to adjustment," Mr Putin said Friday.
"Our offensive operations in Donbas itself do not stop. They are going at a slow pace ... The Russian army is occupying newer and newer territories."
EU calls for war crimes tribunal amid global outrage
The EU presidency on Saturday called for the establishment of an international tribunal for war crimes after new mass graves were found in Ukraine.
"In the 21st century, such attacks against the civilian population are unthinkable and abhorrent," said Jan Lipavsky, foreign minister of the Czech Republic which holds the European Union's rotating presidency.
"We must not overlook it. We stand for the punishment of all war criminals," he added in a message on Twitter.
"I call for the speedy establishment of a special international tribunal that will prosecute the crime of aggression."
French President Emmanuel Macron and US Secretary of State Antony Blinken have joined a growing chorus of outrage in western countries at reports by Ukrainian officials that they had uncovered a mass grave just outside the city containing hundreds of bodies.
"I condemn in the strongest terms the atrocities committed in Izyum, Ukraine, under Russian occupation," Mr Macron tweeted.
Those responsible "will have to answer for their acts. There is no peace without justice," he added.
Mr Blinken said that Russia was behaving "horrifically" and was likely responsible for war crimes.
"This is part, horrifically, of an ongoing story whenever we see the Russian tide recede from the parts of Ukraine that it's occupied," he said.
"We see what's left in his wake. And this latest discovery of apparently 440 mass graves in Izium is a reminder of that," he said, referring to the eastern city where Ukrainian forces have driven out Russian invaders.
Mr Blinken called on Ukrainians to maintain evidence to document atrocities, saying, "There needs to be accountability."
"In many instances, these will amount to war crimes, which I think is the appropriate frame through which to look at this," he said.
