(CNN) — Day after day, in town after town, a police officer and prosecutor go door to door in Ukraine’s Kherson region.

Treading muddy streets, past homes damaged by artillery strikes, they look for those left behind. The two men form a specialist unit that’s traveled from the capital, Kyiv.

A mother and daughter come out to their yard. “We are looking for sexual crimes,” the prosecutor, Oleksandr Kleshchenko, says.

Until early October, this area of the country was occupied by Russian troops. Burnt-out cars litter the fields. The letter ‘Z’ — a symbol used by Russian forces — marks the walls.

The scars of war run deep here. Russia has used sexual violence as a “weapon of war” — a deliberate “military strategy” — in its conquest of Ukraine, United Nations investigators have said. They have even relayed allegations of Russian soldiers carrying Viagra.

Russian authorities have denied accusations of war crimes in Ukraine.

In two weeks of work in the Kherson region, the team from Kyiv has documented six allegations of sexual assault. The real number is almost certainly much higher, they say.

Tatiana, age 56, says she is one of the victims. CNN is withholding her last name and that of her village to protect her identity.

Walking over broken glass, she shows us into her brother’s house, where she says two Russian soldiers forced their way through her door on August 26.

“They walked around those rooms,” she says. “One stayed there, and the other one, who raped me, came in here. He came in, walked a little bit around the room and here in this place, he started groping me.”

“I told him, ‘No, no, I am not of the age that I can give you something, look for younger girls.'”

He pinned her against the wardrobe, she says, and tore at her clothes. “I was crying, begging him to stop, but with no success,” she says. “The only thought I had was to stay alive.”

He warned her not to tell anyone, she recalls. “I didn’t tell my husband right away,” she says, in tears. “But I told my cousin, and my husband overheard. He said, ‘You should have told me the truth, but you kept silent.'”

“I was very ashamed,” she says. “I wish that he and all his kin were dead.”

She spent three days at home, in a daze, too ashamed to step outside. Then, in an extraordinary act of bravery, she says she confronted the Russian soldier’s commander.

“His commander found the head of his unit. He came to see me and told me, ‘I punished him severely, I broke his jaw, but the most severe punishment is ahead.’ Like shooting. The commander asked me, ‘Do you mind this?’ I said, ‘I don’t mind, I wish all of them will be shot.'”

Although the prosecutor, Kleshchenko, and police officer Oleksandr Svidro are looking specifically for evidence of sexual crimes, everywhere they go they are confronted with the horrors of occupation.

In these liberated villages, nearly every building has been damaged by war. Many homes were reduced to rubble.

At their first stop on the day CNN accompanied the investigators, in Bila Krynytsya, a crowd waiting for food handouts surrounded the prosecutor.

The village was behind Russian lines, but never directly occupied. Those gathered round shout that they’ve been abandoned for months, with no help from either Russia or Ukraine.

“Did you report [the damage] to anyone?” the prosecutor asks. “Who would we report it to?” replies a man in the crowd.

A man in the crowd tells the investigators that he was held by Russian soldiers and subjected to mock execution. It’s hard to hear, tales of torture like this are common here, but that’s not the subject of their work today.

Despite the dissatisfaction of these villagers, Ukraine’s counteroffensive in this part of the country has buoyed public hopes that victory might actually be possible — or at least that Kyiv might liberate key Russian-held cities, such as Kherson.

Starting slowly at the end of the summer, and then in large measure at the beginning of October, Ukrainian forces have regained hundreds of square miles of territory that Russia held since the early days of its full-scale invasion.

A short drive down roads pockmarked by shelling, in Tverdomedove, a mother and daughter tell Kleshchenko that they have not heard of any sexual crimes in their one-road hamlet.

Their neighbor, 71-year-old Vera Lapushnyak, sobs uncontrollably. The Russians were kind when they first arrived, she says.

“They said they came to protect us,” she recalls. “But from whom, why — we didn’t know.”

She was widowed more than 30 years ago — she says her husband died in a motorcycle accident — and her son joined the military soon after Russia’s invasion on February 24. She decided to leave, she says, about three months after Russian troops occupied her village.

Months later, after the Ukrainian military liberated her village in a lightning counteroffensive, she returned. Shelling had reduced her roof to its rafters.

“I don’t know where to sleep now,” she says, in tears. “There are no windows or doors. I sleep like a bum.”

She shows us inside. The ceiling of her bedroom has completely collapsed. She’s moved her bed to the only room that still has an intact window.

“I don’t know where to put it so that (the ceiling) won’t fall on my head,” she says. “If it would fall and kill me that would be better, so I won’t suffer. But I want to see my son again.”

As the sun sets at the end of a long day, the two-man team arrives in Novovoznesens’ke, a village where they’ve uncovered two more cases of rape, allegedly by Russian soldiers. The next day, they return to Kyiv, to submit their findings.

Of course, many of these allegations will be impossible to prove; many do not even have a suspect. For now, the team files its reports, and its investigators continue their work, hoping to be able to file charges in the future.

The United Nations says it has investigated cases in Ukraine of “sexual and gender-based violence” against people ranging from 4 to 82 years old. As of September, 43 criminal proceedings had been initiated, according to the UN.

The police officer, Svidro, says most cases of sexual violence go entirely unreported.

The work takes its toll. “It’s psychologically difficult,” he says. “You understand every person is distressed. But this is important work.”