KYIV, Ukraine — The stories of betrayal trickle out weekly or even daily: A villager tips off an occupying Russian military unit about identities and activities of volunteer defenders. A resident of a besieged city clandestinely calls in the coordinates of a Ukrainian troop encampment. A small-town mayor tells neighbors that encroaching Russian troops mean no harm.
For as long as humans have waged war, they have feared the enemy within. Collaboration and treason run like dark threads through the tapestry of nearly every wartime narrative, no matter how triumphal: in ancient Greece, in Revolutionary-era America, in Nazi-occupied France.
And in Ukraine, which is fighting an existential battle to defend itself from Vladimir Putin's armies.
Those who study the phenomenon of collaboration say a choice to betray one's country and compatriots can be motivated by a host of factors: divided loyalties, personal grudge or gain, or an attempt to buy safety for one's own family or community.
"There are many reasons," said Ukrainian military historian Roman Ponomarenko. "It might be based on a person's feelings toward the so-called 'Russian world,' or survival instinct, or be profit-motivated. Or they simply don't care about the country."
In more than five months of fighting off the Russian onslaught, Ukraine has exhibited a remarkable degree of national solidarity. Collaboration, when it does occur, is often a source of scalding shame, a largely taboo topic even among those who have been its victims rather than perpetrators.
The subject surged into the open this month, however, when President Vladimir Zelenskyy very publicly removed two top security and law enforcement officials — the domestic intelligence chief and the country's prosecutor general — declaring that their departments were honeycombed with hundreds of Russian sympathizers or saboteurs.
Neither official was personally implicated, but the episode marked the most serious government shakeup since the Feb. 24 invasion.
"Crimes against the foundations of the national security of the state, and the connections detected between the employees of the security forces of Ukraine and the special services of Russia pose very serious questions," the president said in announcing the sidelining of the two senior officials, Prosecutor General Iryna Venediktova, and Ivan Bakanov, a childhood friend of the president who headed the Security Service of Ukraine, or SBU.
More than 650 criminal investigations involving alleged collaboration or treason have been opened against security and law enforcement officials, Zelenskyy said — a troubling phenomenon in agencies tasked with policing such matters.
Nationwide, at least 1,300 people, including private citizens, are under investigation for collaboration, the head of the national police, Ihor Klymenko, told Ukrainian media in June.
At both the provincial and national level, many prosecutors routinely evade questions about such cases under their jurisdiction. But particularly in areas where Russian forces initially held sway and then fell back — including a swath of commuter towns and suburbs near the capital, Kyiv — allegations of collaboration continue to emerge as investigators struggle to document a vast array of suspected war crimes by occupying troops.
Part of that developing picture is determining who might have aided the Russian forces.
"There were such people among us," acknowledged Mykhailyna Skoryk-Shkarivska, the deputy mayor of Bucha, a once-quiet Kyiv suburb. The town's name became synonymous with gruesome atrocities committed against civilians — some of those likely facilitated, the deputy mayor said, by local people who handed over information after Bucha fell under Russian control early in the war.
About 40 cases of suspected collaboration are under investigation in the capital area, said Andriy Nebytov, the police chief of Kyiv oblast, or region. Consequences of such betrayals were sometimes horrific, he said.
In the village of Motzhyn, Olha Sukhenko, the village head, was tortured and killed along with her husband and 25-year-old son in March, in the war's early days. Ukrainian authorities say she and her family were targeted because of her presumed knowledge of those who were active in the territorial defense forces or otherwise resisting the occupation.
"The collaborators pointed her out to Russians," Nebytov said.
Human rights officials, both Ukrainian and international, have raised concerns about whether, in the midst of a brutal war, accused or suspected collaborators will receive proper due process. At the same time, there are free-speech issues: When does publicly expressing sympathy for the invaders cross over into aiding them?
In some communities, there is little doubt that rough justice has occasionally been meted out. In one desolate village cemetery outside the capital, a local man showing visitors around recently pointed out the grave of a man who had been suspected of aiding the occupiers.
"He was taken care of," he said grimly, refusing to say more.
Often, though, those who took the Russians' side — and feared that neighbors were aware they had done so — fled when Moscow's troops pulled back from areas around the capital, finding haven in Russian-controlled areas or hiding elsewhere, police say. That puts them out of the reach of Ukrainian authorities, at least for the moment.
In some areas either occupied or menaced by Russian forces, some Ukrainian officials are trying to turn the tables on Russian efforts to lure local people into cooperating with them.
In the southern city of Mykolaiv — which is considered a key Ukrainian bulwark on the Black Sea coast, and has come under repeated Russian strikes in recent weeks — the governor, Vitaliy Kim, this month offered a $100 bounty to those who report someone who is acting on Russia's behalf.
Kim told a news conference that nearly 100 tips had been passed along in a single day, with most people not seeking to collect a bounty but merely wanting to help. But the governor acknowledged it was important to prevent a "witch hunt," in which people might try to settle personal scores by leveling a difficult-to-disprove accusation of collaboration.
In the southern port city of Mariupol, which fell to Russian forces in May after a bloody and protracted fight, the exiled mayor, Vadym Boychenko, said afterward that while the battle was taking place, Russia had Ukrainian "spotters" in the city who provided precise coordinates for bombarding critical infrastructure, and who passed along detailed information about when busloads of evacuees would try to make their way out of the city.
Even in parts of the country devastated by fighting, some Ukrainians — especially those who came of age prior to 1991, when Ukraine was part of the Soviet Union — have traditionally felt culturally aligned with Russia. Along the eastern battlefront, where Russian bombardment has reduced many cities and towns to smoldering ruins, Ukrainian defenders have spoken publicly of being taken aback at times by encounters with local people who refuse to believe that Russia is attacking.
Some senior Ukrainian officials now say that sense of kinship was always misplaced.
"Thirty years of our so-called great friendship with the Russian Federation have now resulted in great aggression, a great war," national security adviser Oleksiy Dnilov recently told Ukraine's public broadcaster. "These are the consequences of our imprudent positions over the entire 30 years of our country's existence."
Soon after the war broke out, Ukrainian lawmakers toughened laws on collaboration, allowing for sentences of up to 15 years and confiscation of property. In instances that result in a death or deaths, the penalty can be life in prison.
But often, collaboration isn't an open-and-shut case. Ponomarenko, a scholar of World War II-era Europe, noted that areas occupied by Moscow's troops since the first days of the war, such as the southern city of Kherson, teachers are being ordered to teach a pro-Russian curriculum. The new law technically could open the door to prosecution, which he believes would be wrong.
"It's very complicated to say," said Ponomarenko.
Even the staunchest Ukrainian patriots are tacitly resigned to the fact that both the murky nature and the sheer number of collaboration cases — combined with the urgency of fighting a war whose outcome is far from assured — will likely mean a years-long reckoning.
If Ukrainian forces are able to wrest back control of areas like Kherson, which fell in the war's earliest days, officials say the immediate concern may lie in knitting back together communities shattered by the war's violence. But if the Russians are driven back, more evidence against local people who helped them will inevitably emerge.
"Accountability for collaboration is inevitable," Zelenskyy said in a speech earlier this year. "Whether it will happen tomorrow or the day after tomorrow is another question."