Kyiv, Ukraine (CNN) A week after Russia invaded, the family of 15-year-old Arina Yatsiuk decided to flee their home near the Ukrainian capital by car. Less than 10 miles down the road, they encountered a group of Russian troops.
The soldiers started shooting, then dragged Arina and her 9-year-old sister Valeria out of the back seat. Arina was wounded and put into one car; Valeria was ushered into another.
Valeria was taken to nearby villages where she was found by locals standing at the roadside. The parents of the girls, Denys and Anna were found shot to death in their car.
Arina disappeared on March 3, 2022. According to official Ukrainian statistics, she is one of 345 Ukrainian children who disappeared after Russia launched its full-scale war against Ukraine in February.
According to the Ukrainian government, many of the children who are missing have been taken to Russia. The Russian government isn't denying that it has taken Ukrainian children, in fact it claims it's "saving" them.
Oksana Yatsiuk's aunt told CNN that the family has been looking for Arina since her disappearance. She described the girl with dark brown eyes and braces as a missing child. Her aunt stated that Arina enjoys drawing, make-up, and travel.
"She had big dreams, but the 'Russian liberators' decided everything for her. When we find her, we will carry on with her plans," she said.
The family said they believe the girl, who is now 16, is still alive and "held captive" in Russia.
"I sent official letters to all of the medical facilities, to the Ministry of Health in Russia, Belarus and Ukraine and the official answer I received is that she has not been registered anywhere," Yatsiuk told CNN in a phone interview.
Yatsiuk, who is based in Poland, said she believes Arina had no documents on her when she went missing, which is perhaps why she hasn't been officially registered anywhere.
"I received an official reply that Arina was not recorded crossing the border," she said.
The family has been combing through social media groups, reaching out to groups of displaced people and working with volunteers in Russia and Belarus.
Yatsiuk said Arina's DNA is also regularly checked against the national registers. "She is not on the official lists of dead," she said.
A Russian volunteer who is helping with the search said they believe Arina was taken to a medical facility in Russia and has remained in the country ever since.
The volunteer, who spoke to CNN on the condition of anonymity because their involvement in the search could threaten their safety, said there have been no new leads on the case since the fall.
Arina's disappearance still haunts Marina Lypovetska, the head of projects at Magnolia, a Ukrainian NGO which specializes in cases of missing children.
"She is a witness of war crime. If her younger sister didn't understand that her parents were killed, I suppose that she understood, she herself was wounded and is also a victim of a war crime," Lypovetska told CNN in an interview at Magnolia's office in Kyiv.
Magnolia has received more than 2,600 requests from families and friends of missing children since the start of the full-scale war in February 2022, more than the total number of calls it got over the previous 20 years.
Its 18 employees work round the clock. They are in touch with the families of missing children, offering psychological and legal help. The group is also conducting its own searches using open-source intelligence techniques, public appeals and social media sleuthing to gather information.
Most of the calls coming in are about children from Ukraine's occupied territories or areas hit by heavy fighting.
"Before the war, most cases were runaways, but now, most are directly connected to military actions," Lypovetska said, adding that in the early days of the war, the majority of calls were from desperate families who had lost contact with loved ones in occupied areas.
But a few weeks into the conflict, Magnolia started receiving more calls about children who have been separated from their families during attacks or went missing during evacuations, she said.
And it soon became obvious that some of these children had been sent to Russia.
Under international agreements, including the Rome Statute of the International Criminal Court, the deportation of a civilian population is considered a war crime and forcible transfers of children of one group to another group amount to genocide.
The United Nations' refugee agency said in January that Russia's actions were violating fundamental principles of child protection, Reuters reported.
But Russia has been brazenly open about its actions.
Over the past year, numerous Russian officials have publicly boasted about bringing Ukrainian children into the country. According to their statements, hundreds of children from occupied areas have been deported to far-flung places in Russia, where some have been promptly adopted by local families and given citizenship.
A small group of children described by officials as having been rescued from the Donbas was paraded in front of tens of thousands of people during a rally in Moscow last month. The children were encouraged to hug a uniformed man whom one of the girls referred to as "Uncle Yuri" who "saved" them from Mariupol.
CNN has asked the office of Russia's Commissioner for Children's Rights, Maria Lvova-Belova, for comment on the allegations. It received a generic acknowledgement of receipt, but no reply.
Russian officials and pro-Russian separatists began deporting Ukrainian children across the border to Russia days before Moscow launched its attack on Ukraine. The leaders of the Russian-backed, self-declared Donetsk and Luhansk People's Republics (DPR and LPR) in eastern Ukraine ordered mass evacuations of civilians to Russia on February 18.
According to Russian officials, the evacuation included children living in orphanages and boarding schools in the two separatist-controlled areas.
Volodymyr Sahaidak, the director of a boarding school in Stepanivka, a settlement outside of Kherson, has first-hand experience of Russia's efforts to take away children. The school was home to orphans and children whose families weren't able to care for them, as well as children from families in difficult socio-economic circumstances.
When Russian troops rolled into the southern Ukrainian city in early March 2022, Sahaidak decided he needed to hide his wards from the invaders.
"My biggest fear was that children would be taken to Russia, because I've seen what was happening in Donetsk and Luhansk regions during these eight years of war," he told CNN in a phone interview. "I've seen children being taken to Russia. So I was worried they would be taken and brainwashed to 'defend' Russia."
He said that children who had relatives able to take care of them were sent away, while those who didn't were taken in by the staff of the school.
Sahaidak said the school was repeatedly raided by Russian troops and officials in early June.
He said that "they took all of my personal files, all of the hard drives, all the CCTV cameras and all the monitors and they also took all the Ukrainian history books, as well as a few other things they didn't like."
While he managed to protect the 52 children he had under his guardianship, all between the ages of three and 18 years, he said a separate group of children that had been evacuated to the school from the Mykolaiv region was taken away by Russian troops.
Sahaidak told CNN he managed to reach the head of the Mykolaiv school, who told him the group had been taken -- against her will -- to the Black Sea town of Anapa in Russia. According to Sahaidak, volunteers later helped the group to escape to Georgia. As of February, the children were still there, he said.
Russia's 'rescued orphan' claims disputed
The exact number of unaccompanied children who have been taken to Russia is unclear.
A spokesperson for Ukraine's children's rights commissioner, Daria Herasymchuk, told CNN that as of February 23, 2023, at least 16,221 children had been forcibly deported. However, the spokesperson added, that number includes only the children Ukrainian officials know about. Many more may be in Russia without anyone being aware of their presence.
Andrii Kostin, the Ukrainian Prosecutor General, stated last week that Ukraine had managed to return 307 children. During a meeting with Dunja Mijatovic, the Council of Europe's Commissioner of Human Rights Dunja Kostin stated that "To do more we need the support of the international community."
CNN asked Russian officials about the number children brought to Russia from Russia by relatives. They have not replied to CNN's inquiries. Statements throughout the year show that the number is in the thousands.
According to statements from Russian regional officials, 400 children were sent to a facility in Rostov-on-Don, near the border between Russia and occupied Ukraine, in the first days of the war.
In April, the office of Lvova-Belova, the Russian Commissioner for Children's Rights, said that around 600 children from Ukraine had been placed in orphanages in Kursk and Nizhny Novgorod before being sent to live with families in the Moscow region.
Russia's Commissioner for Children's Rights Maria Lvova-Belova pictured with what her office said are orphans from Donbas who have been sent to Russia's Nizhny Novgorod region. The image was released by Lvova-Belova's office in September. CNN obscured portions of this image to protect the identity of the children.
According to the Moscow regional governor, 800 children from Ukraine's eastern Donbas were living in Moscow as of mid-October. Many of them had families.
Some of the children have ended up thousands of miles and several time zones away from Ukraine. According to Lvova-Belova's office, Ukrainian kids have been sent to live in institutions and with foster families in 19 different Russian regions, including Novosibirsk, Omsk and Tyumen regions in Siberia and Murmansk in the Arctic.
Lvova-Belova herself adopted a 15-year-old boy from Mariupol, according to official statements.
A Kremlin readout of her meeting with Vladimir Putin in February revealed she told the Russian President: "Now I know what it means to be a mother of a child from Donbas -- it is a difficult job but we love each other, that is for sure."
In the same meeting, she said that placing Donbas children into Russian families was the "favorite part of my work."
Russian officials frequently claim that children who are up for adoption are war-torn orphans. According to Ukrainian authorities, most of these children have relatives in Ukraine who are willing to care for them.
Last fall, a desperate father from Kharkiv called the Magnolia NGO. The man's wife had been killed while attempting to flee the fighting and the whereabouts of their 10-year-old son were unknown -- until the father saw a video of his boy on a Russian TV program.
"And in the video they showed the boy's face and said, 'we saved this poor Ukrainian boy, an orphan, and we took him to a hospital in Luhansk,'" Lypovetska, from Magnolia, told CNN.
It took more than two months to reunite the father with his son, Lypovetska said. The NGO and Ukrainian authorities engaged a network of Ukrainian and Russian volunteers, along with lawyers, all trying to confirm the boy's location and negotiate his return.
The boy was eventually found in Russian-occupied Luhansk. His father was unable to travel to the region because he wouldn't be allowed to leave the area and would be at risk of being forced to fight for the separatists, so it was up to the boy's grandmothers to make the long, treacherous journey.
"It's impossible to go to Luhansk from Ukraine, so they had to make a big circle through Russia, cross the border, then back through Russia to Europe, and only then back to Ukraine," Lypovetska said.
A new Russian law that came into effect in May has made it much easier to give Russian citizenship to Ukrainians -- as long as they were "orphans, children left without parental care, or incapacitated persons."
But the Russification efforts go well beyond citizenship ceremonies.
Russian officials frequently talk about Ukrainian children being granted Russian citizenship and participating in nationalistic activities, camps, and excursions as well as being sent "patriotic” schools.
This image was released by the Office of the Children's Ombudsman for the Moscow Region along with a statement that said 14 children from Donbas were granted Russian citizenship in July. CNN has removed portions of the image in order to preserve the identities of the children.
Officials announced in one statement that children from Ukraine were being sent to St. Petersburg boarding schools for the Cadet Corps of the Investigative Commission, a school that educates the next generation of Russian state officials.
Several children from the separatist-run regions in eastern Ukraine were also among a group of almost 200 youngsters who attended a "military-patriotic camp for d