The person who pushed the button that launched the missile that struck 13 Marat Street, Kramatorsk, almost certainly did not know of the apartments that once stood here, the people and families who once lived here, and the lives that were stolen here.

But 60-year-old Valentina knows.

She might have lived on the fourth floor, but all that she owns fell here in the lobby.

She salvages what she can from the Russian strike on February 1 that Ukraine and the U.S. called indiscriminate.

She walked up to her apartment, despite the frequent air raid siren.

She has lived here longer than Ukraine has been independent.

She was in her apartment when the missile struck.

She is lucky to be alive.

Today, she uses it for storage.

This is what remains of her possessions.

The wall that used to have a window into the bathroom is now a window onto the ground below.

That's her bathtub, and the aqua tiles installed by her and her son.

VALENTINA, Resident of Kramatorsk, Ukraine (through translator): I was asleep.

And I was lucky that I was on the other side of the apartment.

Had I been sleeping on the side, you see for yourself.

NICK SCHIFRIN: So, that's your son.

She shows me videos of her son.

In 2014, he went to fight following Russia's initial invasion.

He never came back.

VALENTINA (through translator): On March 23, he would have been 44.

My life has been lived.

For 60 years, I was saving, creating this home, and now it's all gone.

There was a grocery store here.

And they got me some groceries, just strangers, total strangers.

This was the first year they have opened the store.

They called me and asked: "Do you need anything?"

I said: "I have never asked anyone for anything my whole life.

I'm very ashamed.

But I don't have anything."

And they got me groceries.

They said: "This is for you from our family."

That's it.

Everybody left.

I'm here all alone.

NICK SCHIFRIN: Artem Shalata is a Donetsk region war crimes prosecutor who is investigating the strike he calls a violation of the rules of war.

ARTEM SHALATA, Donetsk Region War Crimes Prosecutor (through translator): During this attack, a married couple died.

A 61-year-old woman and her 31-year-old daughter died.

And 17 people were wounded.

NICK SCHIFRIN: He and his fellow prosecutors visit the aftermath of many strikes, and try to find the Russian missile that can be sometimes be linked with specific units.

And they document graves of the Ukrainians whom Russians have killed with overwhelming regularity.

What is the scale of Russian crimes in Donetsk?

ARTEM SHALATA: We are overseeing investigations of more than 20,000 criminal cases, in connection with violations of the rules of war.

NICK SCHIFRIN: One of the most notorious occurred here, the Kramatorsk train station, where the horror of what happened hangs heavy for even soldiers and the memorial marks the most innocent victims.

Last April 8, hundreds of Ukrainians from the east arrived on the platform and inside the station to try and flee the war.

Suddenly, they flinched.

Human Rights Watch investigated the attack and created this animation.

At that moment, a mile-and-a-half above the station, a Tochka-U cluster bomb 20 feet long with 50 bomblets inside exploded and released its deadly submunitions, each with explosions and metal rings.

When they land, they burst into thousands of fragments and create terror.

At least 58 people died, more than 100 injured, one of the war's deadliest moments.

Left behind, the suitcases that would never be used again, the prized possession that would never be held again.

Apparently, the Russians considered the attack tit for tat.

The missile that landed here was spray-painted "Payback for our children."

IDA SAWYER, Human Rights Watch: I mean, absolutely horrific what they did.

This was a known evacuation point.

We counted over 500 people at this train station at the moment of the attack.

NICK SCHIFRIN: Ida Sawyer directs the Crisis and Conflict Division at Human Rights Watch.

IDA SAWYER: This attack at the train station clearly a violation of the laws of war and an apparent war crime.

These are people desperately fleeing war.

We have seen extensive war crimes, crimes against humanity being committed over the past year.

And it is -- it's just one thing after another.

NICK SCHIFRIN: In so many ways, Russia has taken a page from its own playbook and targeted Ukraine's most vulnerable.

This used to be a psychiatric institution, hit by four Russian rockets, one of at least eight hospitals in this city alone struck by Russia, part of what independent researchers call a nationwide campaign against Ukrainian medical facilities.

Physicians for Human Rights mapped every attack on a medical facility between February 24 and December 31.

They counted 707.

If you think this is new, you haven't been paying attention.

Russia has used the same tactics in Syria for eight years.

But now Russia is now committing a new crime.

These children might look happy for Russian propaganda cameras, but each is Ukrainian, stolen from their homeland and forcibly made Russian.

This is the reality.

Russians besieged Mariupol, and forced its children into Russia, including those of Yevhen Mezhevyi.

YEVHEN MEZHEVYI, Father (through translator): I put the children on the bus, hugged and kissed them.

CHILD (through translator): One man said he would be returned in seven years.

People said five or seven years.

CHILD (through translator): They asked me again, do you want to join a foster family or an orphanage?

NICK SCHIFRIN: They told their story in a "Vanity Fair" documentary for The Reckoning Project.

Nataliya Gumenyuk is the group's founding member.

NATALIYA GUMENYUK, The Reckoning Project: From some of the testimonies and also analytical reports and what we hear from the people, there is an attempt to indoctrinate those kids with the different policies, with the different ideas, and actually creating kind of a hatred and denial of the Ukrainian state.

NICK SCHIFRIN: Mezhevyi managed to travel to Moscow and escape with his children to Latvia.

The U.S. says Moscow's actions are taken at all levels of the Russian government, including the top.

Last week, Russian President Vladimir Putin met the presidential commissioner for children's rights in Russia, who said she - - quote -- "adopted" her own Ukrainian child.

NATALIYA GUMENYUK: I think Russia, in particularly, in previous wars in Syria, in Chechnya, they were acting with such an impunity, thinking that nobody would care.

In Ukraine, they made a mistake.

We do care.

We record.

We document.

There is the will of the people of the country to do something.

And that gives a hope that that -- the justice can be sir can prevail.

NICK SCHIFRIN: Ukraine wants to create an independent tribunal to pursue Russia's leadership.

But the U.S. has so far refused to support that, and instead prioritizes the International Criminal Court.

Accountability there will take years, while the Russian missiles keep falling.

The strike blew open a dozen homes and rained debris on the playground.

The same playground where 61-year-old Sergey Seydaliev's children used to play.

He stares at his now-destroyed home, where he lived with his parents and his family for the last 42 years.

There is so much torment here, but it's mixed with a tenacious will.

SERGEY SEYDALIEV, Resident of Pokrovsk, Ukraine (through translator): We lost all of our savings.

This is my whole life.

And now everything is gone.

Everything is gone.

I'm an older man.

But we will make it through.

Life does not stop here.

We will win, for sure, I have no doubt whatsoever.

NICK SCHIFRIN: After all the Russian crimes, most Ukrainians say the only justice would be victory.

For the "PBS NewsHour," I'm Nick Schifrin in Kramatorsk, Ukraine.