War crimes in Ukraine may be unprecedented. So is the country's push for swift justice.

Editor's note: This story contains graphic images and descriptions.

KHARKIV, Ukraine – Alexander Satanovskiy died during a game of dominoes.

He and his friends gathered most evenings at a table in the playground at the foot of the apartment buildings where they all lived. A wooden structure sheltered their seats. On busy days, some players had to stand.

After the war with Russia began six months ago, they often heard air raid sirens and artillery fire echoing in the distance. People had been killed and injured nearby. But Satanovskiy and his friends still gathered to play. He had taken a break from the game for about a week. But for one reason or another – to snap boredom or on a whim, his wife wasn't sure – one day in late June he felt the pull of camaraderie. He sat again at the domino table with about half a dozen others.

It was 5:45 on a summer evening in eastern Kharkiv, Ukraine’s second largest city. Before the war, it would have been a time to walk in the forest, to snack on sweet cherries in the golden-hour light. To play a game in the park with friends.

Out of nowhere, a whistling sound arrived. A bang, pop and a whoosh.

Buildings rattled and glass shattered.

Before dark that evening, investigators were on the scene to try to piece together a picture of what happened.

A 1980s-era Soviet-designed Smerch rocket, most likely launched from Russian soil just 10 miles away, exploded overhead. Its payload of miniature explosives scattered across the overgrown playground.

They thudded into the tufts of grass and scuttled along footpaths adjoining several of the residential apartment buildings, spreading like drunkenly tossed dice.

Then, like so many firecrackers, they exploded, and with them, shrapnel.

Two dozen people fell to the ground, a jumble of torn ears and shredded limbs.

The domino table was soaked in blood.

Someone helped Satanovskiy bandage his leg as blood gushed from it. But after about 10 minutes, he began to wheeze. He didn't realize it at first, but he'd also sustained a deep wound on his right side, close to his stomach.

As the long evening shadows stretched across the grass, a crew zipped him into a body bag. He was one of five to die.

"This is how we live now," said Anna Satanovskaya, his 84-year-old widow, the next day.

She sat on a sofa bed in the three-room apartment they had shared, with its balcony that overlooks the place where he died. Through tears, she talked about 82-year-old Alexander. How he was always singing a song to himself. How he worked as a mechanical engineer in a sewing machine factory. How he was a tender and attentive husband and father. How he dreamed of someday visiting Cuba.

How he had beautiful handwriting.

"Who will punish them?” she asked between sobs, as the low-decibel thud and rumble of artillery from the nearby front line could be heard in the distance.

“Who can punish the Russians, please tell me?"

A team of war crimes investigators had already begun the work they believed would do just that. Within an hour of the explosion, they were on the ground with cameras, measuring tapes and clipboards for notes.

They would gather bits of shrapnel, log measurements, interview witnesses.

The cluster bomb, though not banned by Russia, Ukraine or even the United States, is barred under a treaty signed by 123 countries, according to the Cluster Munition Coalition, an international civil society campaign working to end their use. The bomb's popcorn patchwork of exploding fragments is meant to mow down rows of soldiers.

But the explosion, investigators had already concluded, struck a residential neighborhood that had no obvious nearby military targets.

Alexander Satanovskiy’s life had come to a sudden and unexpected end during Russia’s unprovoked war in Ukraine.

To the investigators, it looked like a war crime. It looked like murder.

An unprecedented investigation begins

Across Ukraine, even as Russian tanks roll and rockets fly, teams are investigating deaths like Satanovskiy’s and thousands of other suspected war crimes.

Ukrainian and international investigators, prosecutors, police, security services, and forensic and ballistics experts take part, often researching dozens of deaths each day.

More than 1,000 Ukrainian prosecutors have fanned out across the country to collect war crimes evidence. This includes fragments of missiles, rockets and artillery shells; DNA samples from human remains; victim and witness testimony.

It includes photos, video and detailed notes from investigators as they inspect damage. Sometimes bodies are exhumed. Soil samples taken. Small pieces of debris are analyzed. In some cases, sophisticated laser scanners are deployed to build up a digital picture of crimes scenes. Eventually, cellphone data or radio intercepts may be located.

Their goal is to investigate and document alleged crimes committed by Russia's military. For now, the work is focused on the Russian military's everyday violence against civilians as opposed to the higher-stakes effort to build a case against Russia's president, Vladimir Putin.

USA TODAY spent weeks following investigators to the scenes of suspected war crimes, sometimes arriving – as in the case of the cluster bomb at the playground – just after attacks had ended, even before the victims' bodies had been removed.

Experts say the sequence of judicial steps needed to prove a war crime is similar to an ordinary criminal prosecution: Evidence shows the nature of the crime. Witness interviews establish the events. Suspects are identified – not simply “Russia” as an aggressor, but individual soldiers and commanders. This is less impossible than it sounds; indeed, many Russian soldiers have already been taken as prisoners of war.

Ultimately, if investigators succeed, the suspects are charged, convicted and sentenced.

Yet until recently, many of Ukraine's prosecutors had little direct experience in war crimes work, despite their dark blue vests emblazoned with the words "War Crimes Prosecutor." That job simply did not exist before the war, and the sum total of their training is often just a few days of online tutorials and videos, according to a dozen such prosecutors interviewed by USA TODAY over more than two weeks in June and July.

For this reason, Ukraine has drafted a dizzying array of overseas experts and specialists to assist its investigations.

The political decision to wage war – however indefensible the reason – is not necessarily the same thing as committing a war crime.  

War crimes under international law include atrocities against people or property, murder, ill-treatment, sexual violence, forced deportations, hostage killing, torture, plunder or destruction of public property and devastation not justified by military necessity. War crimes can be committed against diverse victims, both civilians and soldiers.

News reports and time spent with investigators show all of these things have and are taking place in Ukraine, though Putin, his senior advisers, cabinet ministers and Russian state media have repeatedly rejected without evidence the war-crimes allegations as hoaxes staged by Ukraine and its allies. They have inundated the Russian public with false and misleading counterclaims against Ukraine. Moscow has charged almost 100 Ukrainian armed forces personnel with crimes against humanity and proposed its own international war crimes tribunal backed by Bolivia, Iran and Syria.

"Our investigations are about accountability and justice," said Iryna Venediktova, until recently Ukraine's prosecutor general, its most senior legal official. She was the first woman to hold the role, which had seen a number of her predecessors resign or be forced out amid claims of ineffectiveness or graft. Security at her office in central Kyiv was tight. Sandbags lined the doorways. In public, she often wore a bulletproof vest.

"They are about preventing further atrocities in Russian-occupied territories. Holding trials may save the lives of Ukrainian citizens living under occupation," she said.

Time spent observing these investigations reveals that pursuit of justice in wartime is far from clear.

Ukraine's investigators balance their limited training against a seemingly unlimited wave of cases. Public pressure for convictions bumps up against international scrutiny of their justice system.

Many attacks on civilian infrastructure, or ones that result in the death or injuries of civilians, are being investigated as suspected war crimes under the Ukrainian criminal code. Some of these may ultimately not be prosecuted after the investigation is complete if they fail to meet the legal threshold for war crimes under international humanitarian law, or if the perpetrators cannot be identified.

A civilian death or destroyed school or home isn't necessarily enough under international law to prove that a war crime took place. Prosecutors typically look for evidence of intent – that it wasn't an honest mistake. They consider whether there is any significant military target nearby. Soldiers in war must also show regard for protecting civilian lives, and prosecutors look for evidence that soldiers have neglected this duty, based on the precision of the weaponry and where it was used.

"Depending on the situation, some of these incidents and issues can be fiendishly complex, requiring significant tenacity and skill to prove in a courtroom," said Nigel Povoas, a British Queen's Counsel, one of the country's most senior lawyers appointed by the Crown. Povoas has led the prosecution and investigations of some of the world’s most notorious international criminals and is now working in Ukraine for the Internationally led Atrocity Crimes Advisory group, which advises the government on its war crimes cases.

The investigators themselves must improvise; there is no blueprint for this kind of work in an active war zone, where more artillery may descend even as crews are photographing victims and diagramming crime scenes.

Suspects can feel abstract or completely unreachable if they are in Russian territory, from which most rockets are launched.

With war ongoing and no signs of either side letting up, the sheer volume of allegations is also staggering.

There are now more than 26,000 such probes in Ukrainian settings as diverse as kindergartens, private homes, alleyways, parks, warehouses, malls, train stations, city streets, maternity wards – even a nuclear power plant.

Then there is the institutional reality of Ukraine itself, a country that has long been plagued by a lack of judicial rigor and corruption. Ukraine ranked 122nd out of 180 countries on the 2021 Corruption Perceptions Index by Berlin-based Transparency International. This ranked it the second most corrupt nation in Europe, behind Russia.

Some of the more high-profile cases may one day wend their way to the International Criminal Court in The Hague, Netherlands, which claims universal jurisdiction for war crimes events. Or to a specially convened international tribunal similar to the Nuremberg trials that dealt with Nazi Germany’s war crimes. Russia's veto power on the U.N. Security Council means that the council likely won't be able to establish a formal U.N. tribunal for Ukraine similar to the one that dealt with massacres, ethnic cleansing, systematic rape, crimes against humanity and genocide in the former Yugoslavia.

In some cases, Ukrainian families and the public have pushed for quick results – jail time, executions, vengeance – while legal experts have urged a slower, more deliberative process.

"We are trying our best to manage everyone's expectations," said Oleksii Boniuk, who chairs Ukraine's so-called Mobile Justice Teams, rapid-reaction war crimes investigation units that are housed inside the country’s prosecutor general's office – similar to the U.S. attorney general's office.

That balancing act has led the investigative process into uncharted territory in modern warfare. Ukraine's war crimes investigations began within days of the war's outbreak, a scenario for which there is no precedent.

Rather than wait for an international tribunal that might convene someday, months or years from now, Ukraine will prosecute most of its war crimes cases itself, with its own judges, in its own courts.

A defendant sits in a glass cage

Mikhail Kulikov sat in a glass box.

His head was shaved. He wore gray cargo pants, a sweatshirt and rubber slippers.

He pressed the fingers of one hand lightly against the other, forming a steeple with his hands. He tapped his fingers together slowly.

Kulikov, 32, a Russian soldier, a father of two, was on trial.

The courtroom in Desnyansky District Court in Chernihiv, 50 miles from Ukraine's border with Belarus, was hearing the case that accused him of a war crime.

Kulikov pleaded guilty to firing a shell from a Russian tank on a residential apartment building in Chernihiv, a city known for its grand churches and cathedrals and parks with abundant summertime vegetation.

The court building itself was standard municipal fare.

But inside, the courtroom featured one element not used in the U.S. justice system: a reinforced class enclosure – a box – for defendants.

Human rights groups have denounced the use of such cages as a visual threat to presumptions of innocence. To those not familiar, the cages can make the defendant seem like an exhibit, something bordering on voyeurism.

There was an initial crush of people lined up in a narrow hallway outside the court before the hearing got underway. Once inside, people crowded around the glass box to get a close-up look at Kulikov.

Stony-faced guards made sure that observers and members of the media who had come to watch the proceedings did not get too close.

Kulikov came across as confident.

Though he had entered a guilty plea, he said he'd only been following his commander’s orders. He expressed remorse for what happened but otherwise said little. Every few minutes, he would lean over as his translator whispered in his ear.

Prosecutors asserted Kulikov was guilty of a war crime, based on firing on a civilian apartment building. The verdict would be decided by a judge. Kulikov's guilty plea could lead to a more lenient punishment.

But there were challenges to the government's case.

No one had died in the shelling.

One of the witnesses, an elderly woman, said she had later found a soldier from the tank hiding in a barn where she keeps her chickens. But she said she couldn’t be completely sure the man was Kulikov. A second witness admitted he was down in the apartment building's bomb shelter when the incident took place.

The Russian soldier also said his superiors told him to fire on the building because someone holding an anti-tank missile had been spotted in or near the apartments. That could be a plausible defense. His commander was already back in Russia as part of a prisoner swap and couldn’t be questioned.

The hearing’s lead prosecutor stressed several times that Kulikov was aware he was shooting at a residential area and there were no military facilities nearby. Yet it was not entirely clear how this prosecutor had been able to establish this.

There were other red flags around how the Ukrainians had treated Kulikov.

In March, Kulikov spoke at a press conference organized by Interfax-Ukraine, a news agency. He appeared with two other Russian servicemen, all prisoners of war.

“The Ukrainian people are not afraid of anyone. They will stand up for their land to the last,” Kulikov said at the press conference. “(Russian) parents, block the roads, do not let your children go, do everything to make the Russian troops turn back.”

The statement may have been a reflection of Kulikov’s remorse.

But according to the Geneva Convention – several combined treaties and protocols agreed by every country that define how soldiers and civilians should be treated in war – a detaining authority has an obligation not to parade POWs or allow them to be exposed to the public. That, in itself, can be a form of war crime, even if it seems a slight one compared to the volume of atrocities alleged against Russia's military since the war started.

As the Chernihiv hearing came to a close, the court's police wardens dragged Kulikov back to his cell.

In early August, Kulikov was given a 10-year prison sentence.

A shopping mall lies in ruins

Ljudmyla Brygadyrenko sat on a bench in a small park directly adjacent to what had once been a shopping mall, waiting to learn whether her daughter was dead.

Tatiana, 22, had worked in a kiosk in the center of the mall selling cellphone accessories. She and her boyfriend were planning to get married. That was before the missile strike, before the mall here in Kremenchuk, central Ukraine, became internationally recognized, one of the conflict's most visible alleged war crimes.

Brygadyrenko, 55, had been waiting for two days with no word from her daughter.

"She put on a new dress when she left for work," said Brygadyrenko, recalling their final interaction. "I looked at her but didn't kiss her."

About 100 yards behind the bench, over a hedge, the ground was charred.

Debris was everywhere.

A crane groaned in the background, as it unearthed chunks of concrete from the tangled wreckage of what once had been a supermarket.

Parts of the supermarket's fish counter were splattered nearby. Charred meat was visible, poking out from underneath piles of concrete. Every so often an aroma of rotting seafood wafted in on a cloud of dust kicked up from the crane's labored digging.

"Right now we're only finding small fragments of bones," said Anton Stolitniy, a prosecutor from the neighboring Poltava region.

Stolitniy had been deployed to the Kremenchuk mall site for a few days.

Two days after the attack, the death toll had reached 20.

Ukraine's security services released images and video showing a Russian missile approaching the mall and exploding on impact.

It was a direct hit on a civilian building far from the front lines.

The missile unleashed a massive fireball.

"The number of victims is impossible to imagine," Ukraine’s President Volodymyr Zelenskyy said on Telegram, a social media app popular in Ukraine and Russia, as he spoke of up to 1,000 people being inside the mall.

CCTV captured from a nearby park showed people running for cover as a second Russian missile hit a factory, sending shrapnel and debris flying into a lake.

Emergency workers attempting to reach trapped civilians were met by plumes of thick black smoke. The mall’s roof and walls started to collapse.

As survivors and bystanders tried to clear the rubble and search for the missing, many noticed the ground was exceptionally warm.

The fire inside was so hot it had melted metal and glass.

Venediktova and a team of investigators arrived at the scene the next day.

She said the attack constituted a "war crime" under Ukrainian law. In a joint statement, leaders of the Group of Seven countries, including U.S. President Joe Biden, came to a similar conclusion.

A day after Venediktova's visit to the scene, scores of firefighters, emergency personnel and investigators were still excavating the site. They were hoping to unearth more evidence, including human remains. Some people were still missing, though the focus was on search-and-recovery, not rescue.

As the temperature approached 95 degrees angle grinders could be heard cutting through buckled steel beams at the hulking, blackened scene. Firefighters rested in small pools of shade.

Stolitniy said that while each loss of life in the mall was an absolute tragedy, some of the most important evidence that could be collected in the investigation was identifiable pieces of the missile – hard facts that could tie a crime scene to a particular Russian military unit and, potentially, to the specific commander who gave the order to fire it.

He would not say what, if anything, of that nature had been found in the Kremenchuk mall. Nor would an officer from Ukraine’s domestic security service, known as the SBU, who was observing the scene.

"It's possible we're not going to find anything else that looks like a person," Stolitniy said.

Still, Brygadyrenko sat on her bench waiting for news.

Tatiana’s father had submitted a DNA sample to investigators.

The family had been to all the area hospitals and police stations. Her boyfriend was down at the morgue. There was no sign of her.

In recent weeks, amid an uptick of Russian missile and shelling attacks on civilians across Ukraine, Brygadyrenko had implored her daughter to go to a bomb shelter across the street from the mall when the air raid sirens sounded. It's something many Ukrainians have become blase about because of the frequency of alarms, the vast majority of which end without incident.

Evidently her daughter had ignored this advice.

"She loved life, and Russia took that life," the mother said.

"She graduated from a culinary school,” she said, before grief abruptly halted her speech. “I told her, 'Go, at least you will be able to cook for yourself.’”

The following week, investigators located Tatiana Brygadyrenko’s teeth in the mall's rubble, matched to her dental records. Her mother was also able to identify a necklace.

It had a tiny cross on it.

A missile falls next to a school

The elementary school in Kharkiv sat next to an enormous crater in its side yard, where apple trees had grown.

A Russian missile hit the schoolyard, blowing out hundreds of windows and destroying many classrooms.

Elena Fomichova, the school's director, was organizing parents and former students to help clean up the mess.

"Just the other day there were kids playing soccer right over there," said Fomichova, pointing to a field about 50 yards away.

Before the war, before hundreds of thousands of Ukrainian children fled for safety overseas, before the coronavirus pandemic, Kharkiv's school No. 29 had about 300 pupils.

Few children remained after the war began, and in June, class was out for the summer. No one was inside when the blast hit.

"Look, this is a school, it's not a military target. There are no military targets around here. Only a hospital a few streets away," said Roman Petrenko, the prosecutor responsible for the district in north-west Kharkiv that administers school No. 29.

But even here, truth can be hazy, with moving parts and multiple explanations.

Not far from the soccer field were a series of brick buildings surrounded by a high wall topped with barbed wire. Every few minutes a few soldiers would quietly come or go from a small gate connected to the wall.

At first, Petrenko was adamant that the buildings next to the school had no military function. Eventually he conceded the site housed some buildings Ukraine's military was using to do work related to radio communications. He said he did not know more.

Could the Russian missile that struck school No. 29 have been intended for the buildings next door instead of the school? It's conceivable. It doesn't excuse the strike on the school, but it could make it a mistake rather than a crime.

It may also suggest that in some cases, Ukrainian military infrastructure is close to civilian buildings.

At another school in Kharkiv that was hit by a missile strike, it seemed apparent  that Ukrainian soldiers had been sleeping there. And the school settings again expose the difficult questions of wartime justice.

If soldiers are using an empty school as barracks, does that mean the school no longer constitutes civilian infrastructure?

This may sound like legal hair-splitting when Ukraine as a whole has been invaded by Russia and may, in fact, have no option but to fight back from urban settings in close proximity to where civilians live and work.

Yet some war crimes legal experts say, as far as international convictions go, it isn’t.

“When NATO forces bombed the Chinese embassy in Belgrade during the war in Kosovo, the Chinese government considered bringing war crimes charges. One of the reasons it didn’t was because NATO said it was using old maps and it had been a clear mistake. Even if there had been a conflict situation, it would have been impossible to prove,” said Toby Cadman, a London-based expert in international criminal law who has worked on war crimes cases connected to Kosovo, Syria and elsewhere.

Still, after humanitarian group Amnesty International's Ukraine operations published a report accusing Ukraine of endangering civilians by basing some soldiers in empty schools and near hospitals, Hanna Maliar, the country's deputy minister of defense, noted that Ukrainian troops and artillery needed to be in towns and cities to protect civilian infrastructure or "Russian forces would simply sweep in unopposed."

Dmytro Kuleba, Ukraine's foreign minister, accused Amnesty of fostering disinformation and aiding Russian propaganda. Other Ukrainian officials and some international ones argued that because Russia is the aggressor, any tactics used by Ukraine to defend itself were justified.

A larger truth remains elusive

One hundred and eighty days  into the war, Ukraine maintains control of most of the sovereign territory it held before the invasion. It has started ramping up strikes on Russian-held bridges and weapons depots.

The litany of war crimes allegations against Russia also continues to grow.

Ukrainian officials believe that Russia killed at least 53 Ukrainian prisoners of war at a detention camp in Ukraine's eastern Donetsk region, possibly by mining the barrack with a "flammable substance" that led to a massive fire.

But it may be too soon to conclude whether there is sufficient evidence to prosecute Russian actors in an international legal setting for genocide, a category of war crime that can be committed during war or peace and is typically defined as an intent to destroy, in whole or in part, a national, ethnic, racial or religious group.

Zelenskyy and other top Ukrainian officials have repeatedly described Russia’s atrocities in these terms, as have some U.S. lawmakers.

Yet there are potential hurdles.

“It is much harder to prove from a judicial perspective that genocide is taking place in Ukraine than it is from an analytical or moral or historical perspective,” said Eugene Finkel, a Ukrainian-born political scientist and noted genocide scholar who teaches at Johns Hopkins University and has concluded that genocide is happening in Ukraine.

“You need to prove intent, motivation; you need to explain the logic, make an argument. As a historian I can look at the bigger picture and look at who gets killed and why. That’s more difficult for prosecutors who mostly look at what happened in each individual case,” he said.

Ukraine has also identified about 600 top Russian officials – cabinet ministers, senior military commanders, propagandists – who it wants to hold accountable for the "crime of aggression." The crime of aggression targets those most responsible – leaders – for the act of invading, attacking, annexing or bombing another country.

It has been argued successfully internationally only at the Nuremberg trials and at the Tokyo tribunal, which also was connected to World War II, according to Jennifer Trahan, a legal expert who teaches at New York University.

Whether Ukraine will be able to engineer an international tribunal for this kind of prosecution remains to be seen, though it did convict and sentence in its own courts – in absentia – former president Viktor Yanukovych of the crime of aggression over his attempts to quash a 2014 pro-Western uprising.

“We understand that this is a long-term play,” said Yuriy Belousov, Ukraine's chief prosecutor responsible for war crimes cases.

“We understand there are limitations. We don't have physical access to these people. We also know if they leave Russia, go somewhere, justice will wait for them there.”

An early atrocity remains unresolved

One person who isn't prepared to be patient is Natalia Verbova.

Her husband was one of eight men killed in Bucha by Russian paratroopers in March.

The Kyiv suburb saw some of the worst Russian atrocities, according to investigators, witnesses and human rights groups: residents raped and killed in basements; people subjected to mock and summary executions; snipers firing on unsuspecting civilians or those trying to run away; people forced to smell corpses. Hundreds were buried in mass graves.

"The torture (the Russians) inflicted. The physical and mental pain. They must experience it themselves," said Verbova as she fiddled with a box of matches while sitting on a bench near where her husband was killed.

Verbova, a 50-year-old nurse, told the story of her husband's death, something she has done many times. It never gets easier.

Eyewitness accounts and video, some of it first published in the New York Times, have established Andriy Verbovyi and the others were marched to their deaths at gunpoint.

They were members of a poorly equipped civilian militia manning a makeshift checkpoint – they had a grenade, a pair of binoculars and a rifle among them – when they went into hiding as Russian airborne troops advanced on Bucha, just north of Kyiv.

Before the war, the men were civilians.

Verbovyi, 55, was a carpenter whose deft skills earned him the nickname “golden hands.”

"He could make anything from scratch," his wife said. "He approached everything in a humane way. He tried to help everyone, give advice, do things for them."

The men hid directly opposite the checkpoint at 31 Yablunska St.

Valera Kotenko, who owned the home where they hid, used to bring them hot tea and coffee as they stood for hours outside in the cold. Now, as they stayed out of sight and hoped the Russians would pass by, they sent messages by text to wives and girlfriends and parents.

"His last words were 'I love you but please don't call me again.' He was afraid of making noise. They were surrounded by Russians and spoke only in whispers," said Verbova.

On the morning of March 4, the Russians found them.

Images taken from CCTV footage show nine men, each with one hand placed on their heads and the other holding the belt or pants waist of the man in front, being led up the street to a nearby office building at 144 Yablunska St.

Andriy Turbar, Bucha's deputy prosecutor, said the men were lined up against a wall in a parking lot, beaten and made to pull their sweaters over their heads. Verbovyi and another man, Ivan Skyba, were taken inside the office building for questioning.

It was here that Verbovyi was shot and killed.

Skyba was then taken back to the parking lot, from where he and the remaining captives were led around a corner to a small courtyard.

Witnesses heard gunshots. The men were not seen alive again.

"People in Bucha were killed simply because they were Ukrainian,” said Turbar. "We don't have another explanation."

The bodies laid there until early April, when the area was liberated by Ukrainian forces. Their families had little idea what had happened to them.

Even now, investigators are finding bodies in Bucha, according to Serghii Lyakhovych, 28, the town's medical examiner. A few days before USA TODAY visited the area this summer, investigators exhumed seven bodies found near a Russian trench on Bucha's outskirts. The victims had been shot in the head and knees. They wore jeans and sneakers and T-shirts. Likely civilians, said Lyakhovych.

The courtyard at 144 Yablunska St. still exhibits evidence of how Verbovyi and the other men from the checkpoint were executed.

Gun-shot markings can be seen on a series of steps and across a back wall. They are low to the ground. The men almost certainly died on their knees.

Photos from the scene show some of the men with no shoes on. At least one had his hands bound. Their bodies look rigid and twisted. One man’s foot appears to be caught in a chain-link fence, partly held aloft there by his sock.

Verbova visits the courtyard often with her grown son. They bring flowers and candles. Verbovyi’s body was dumped there with the others after he was killed inside the building.

"My husband always liked to buy and light candles when we went to visit relatives and friends (at the cemetery). So I do that for him now,” she said.

Yet Verbova is unsettled by her understanding of the status of the investigation. It's too slow, she can't see any noticeable progress and she's had little contact with prosecutors, she says. She is also upset that authorities keep demanding additional proof her husband was working for Ukraine's military when he died. This has a bearing, she says, on the compensation she is due from the state.

“I am really disappointed – why haven't those criminals, those Russians, been found? Why isn't an international tribunal dealing with them?” she asked.

One aspect in particular troubles her: Skyba, the man with whom her husband had gone into the building at 144 Yablunska St., emerged from the building alive. After being taken to the courtyard where the other men were shot and left for dead, he survived that episode, too.

In a new BBC documentary, Skyba explains how he narrowly avoided death, by playing dead.

Verbova feels it made him out to be something of a hero.

“I have a lot of questions for him,” she said. “How did the Russians know they were hiding at 31 Yablunska Street? They hid there for almost a day. Why didn’t they split up?"

In a phone interview, Skyba said he has been cooperating with a probe handled by the SBU, Ukraine's domestic security agency. Ukraine’s prosecutor general’s office declined comment, citing an open legal case.

In mid-July, Zelenskyy removed Venediktova from her role as prosecutor general when he also relieved the head of Ukraine's domestic security agency from his duties.

Both of the organizations they led, Zelenskyy said in explaining their dismissals, were riddled with Russian collaborators. He said more than 60 former employees of the two powerful organizations were actively working against Ukrainian interests and more than 650 treason cases against Ukrainian law enforcement officials had been opened. A representative for Venediktova did not return a request for comment on her firing, which was later upheld by Ukraine’s Parliament.

Striking a balance as bombs fall

Russia has fired almost 3,500 missiles at Ukrainian cities, according to Zelenskyy.

Many have been shot down or have failed to hit a target.

Others simply don’t detonate. Many, when investigators unearth them, resemble little more than gnarled scrap metal.

Russia says it is using high-precision weaponry to target military infrastructure. Yet most of the fragments of missiles, rockets and artillery shells Ukrainian investigators collect are old, unguided, Soviet-era.

A lot of this evidence is stored in undisclosed locations, often warehouses, like the one overseen by Volodymyr Homenko, a former SWAT team instructor who runs an explosive ordnance disposal unit at Ukraine’s national police, part of the ministry of internal affairs.

There are about 20 of these warehouses full of ballistics evidence across Ukraine.

Homenko’s was situated on Kyiv’s outskirts.

Inside, the remains of munitions were separated by type and laid out on the floor: Iskander missiles, Smerch cluster rockets, aerial bombs, shells. (Ukraine’s domestic security agency swiftly removes any higher-tech weapons recovered from crime scenes, according to Homenko. It does this so its ballistics experts can study and even copy the technology.)

The building has seen better days. The entrance was secured by a single padlock.

Close to the front door, a supermarket shopping cart with its wheels cut off was stacked full of land mine tops. Small pools of dingy water and discarded fast-food packaging shared the floor with thousands of neatly sorted exploded and unexploded weaponry. On a rear wall, someone had scrawled in red, in all caps, what appeared to be the word “DEATH.”

Homenko explained how some of the missile parts can be traced back to the specific Russian military units that fired them through their serial numbers, something that could prove useful if certain war crimes cases go to court.

In March, Russian offensive positions were less than three miles from this spot; Homenko and 25 of “his guys” had suited up in military tactical gear, grabbed their weapons and were ready to engage the enemy before Russia’s forces retreated.

Back then, this warehouse was receiving “a truckload a day” of potential munitions evidence, Homenko said. By late summer, the flow had trickled to a few pieces a day.

"Each of these strikes has 100 stories behind it, one worse than the next," said Amed Khan, an American human rights activist and philanthropist who has spent much of the war traveling Ukraine and helping to procure humanitarian supplies.

Still, Ukraine's quest for justice continues to put its investigators in different versions of the same difficult situation. Limited resources and training. Expanding cases. International scrutiny. Public pressure for convictions.

All amid a threat to their own safety

This is something Oleksiy Filchakov, Kharkiv’s chief prosecutor, knows all about.

He has a few rules he and his team of investigators stick to when investigating war crimes in the “gray zone,” an unofficial contact line that separates Ukrainian territory from that held by Russia’s military.

No more than two vehicles. If there are more than 10 people in the group – investigators, explosives technicians, forensic specialists – switch all cellphones off. Don’t stay at any one crime scene for more than two hours; three is usually the absolute maximum.

The Russians snoop on cellphone networks and are prone to target clusters of cars and people in this area – especially those who want to hold them to account, he said.

“Armored cars don’t really protect us,” Filchakov said in an interview in his Kharkiv office. It sits on a nexus of streets surrounded by bombed-out and abandoned buildings.

Underneath a khaki shirt with sleeves rolled up to his elbows, Filchakov wore a military olive green T-shirt similar to the one that Zelenskyy has favored since the war's start, instead of his former navy suits, white shirts and ties. The T-shirt has come to symbolize strength, patriotism, Ukraine's defiance to Russia's war.

“Maybe against small pieces of shrapnel, but if there is a direct hit from the drones and banned rocket systems Russia uses, nothing will remain of this armored car. We have gotten used to arriving at a scene, then having to take shelter in a basement,” he said.

Filchakov had originally arranged for USA TODAY to accompany his investigators to a crime scene in the gray zone outside central Kharkiv.

He called it off at the last-minute after receiving an intelligence update.

“Too dangerous,” he said.

“Even being in this room, we are also in danger, because the positions of the Russian military are only 20 km (12 miles) from this place. This building is a target.”

Most attacks happen during the night.

“They start at 23:00 hours and you could set your clock to them,” said Nils Thal, 35, a German firefighter from Nuremberg who spent about eight weeks in Kharkiv this summer embedded with Ukrainian emergency response units.

Thal heard the sounds made by the cluster bomb that killed Satanovskiy. He was standing on the roof of a fire station. He had gone up there to drink a cup of coffee. He later helped Ukrainian investigators as they zipped Satanovskiy up in a body bag.

But the missiles and shells also strike during the day. It was Filchakov who alerted USA TODAY to the cluster bomb attack that killed Satanovskiy.

"There was no smoke, only pops and flying fragments. The fragments were large. I was struck by one as thick as a finger," said Volodymyr Olkhovik, 79, who was seated at the bench playing dominoes on the side opposite to Satanovskiy.

Olkhovik escaped with a broken leg and shrapnel in his back.

Olkhovik, like Satanovskiy, hadn't planned to play that day either. He had only decided last minute to stop by on his way back from the grocery store.

Since the war erupted on Feb. 24, the U.N. has verified more than 5,000 civilian deaths, though the true figure may be far higher.

The missiles and shells appear to fall down from the sky randomly.

On a school one minute. On a sports hall or popular shopping mall the next. On an unremarkable playground, where men like Satanovskiy like to play dominoes and aren’t expecting to die before dinner on a warm and pleasant summer evening.

And in the hours that follow, investigators will arrive to begin their task again.

"What we need to do this work is time," said Filchakov. "We need more time."

Contributing: Jessica Koscielniak, Iryna Dobrohorska, Kostya Ilianok.

This article originally appeared on USA TODAY: How Ukraine pushes for justice in alleged Russian invasion war crimes