KIEV, Ukraine — For two and a half days in October, Leonid Razvozzhayev, a little-known leader of the Russian political opposition, moved furtively from one part of Kiev to another, meeting with political allies and human rights experts about seeking asylum in the West.
At times, he was sure he was being followed. He was right.
On a Friday afternoon in clear daylight, masked men grabbed Mr. Razvozzhayev and shoved him into a black van outside the office of a lawyer who was preparing his asylum application on behalf of the United Nations High Commissioner for Refugees.
The van sped away. Mr. Razvozzhayev’s personal belongings were left behind.
More than the prosecution of the punk band Pussy Riot or the criminal inquiries into numerous opposition figures, the abduction of Mr. Razvozzhayev has showcased the Kremlin’s willingness to employ aggressive — even illegal — measures to suppress the political critics of President Vladimir V. Putin.
It also fits a pattern of recent cases in which people seeking protection in Ukraine were instead returned to the countries they fled, in violation of Ukrainian law as well as international laws and treaties that protect asylum seekers.
Ukrainian officials have refused to investigate Mr. Razvozzhayev’s disappearance, saying he is not a missing person.
“We see a problem of disrespect for international law on the part of Ukraine,” said Maksim Butkevych, a rights advocate with Social Action Center in Kiev.
Russian officials have also refused to open a criminal inquiry into Mr. Razvozzhayev’s complaints.
But this week they said they planned to charge him with illegally crossing the border into Ukraine by using his brother’s passport to buy a train ticket.
Other rights advocates say the actions of both Ukraine and Russia should be examined, and Mr. Razvozzhayev’s lawyers say they expect the European Court of Human Rights to intervene.
“If any government was complicit in the abduction of Leonid Razvozzhayev, that government committed a grave violation of Mr. Razvozzhayev’s right under the 1951 Refugee Convention to be protected from involuntary return,” said Mark Hetfield, the interim president of the Hebrew Immigrant Aid Society, a nonprofit group whose lawyers in Ukraine were preparing Mr. Razvozzhayev’s asylum application.
After Mr. Razvozzhayev resurfaced two days later outside a Moscow courthouse in Russian custody, Vladimir Markin, the spokesman for Russia’s top federal investigator, insisted that he had “turned himself in” — an assertion flatly contradicted by interviews with Mr. Razvozzhayev’s wife, lawyers and associates who saw him in Kiev.
While Russia could have requested his extradition legally, international rights monitors say Ukraine routinely flouts normal procedures.
In 2011, a Palestinian engineer, Dirar Abu Sisi, who had applied for Ukrainian citizenship, was pulled off a train traveling between Kharkiv and Kiev.
Weeks later, the Israeli authorities confirmed that Mr. Abu Sisi, whose wife is Ukrainian, was in jail in Israel, charged with helping Hamas develop weapons, including Qassam rockets.
In December 2009, Khamidullo Turhunov, a refugee from Uzbekistan, disappeared in Kiev, and though there has been no official acknowledgment of his whereabouts, his family says that he is imprisoned in Uzbekistan.
In a 2010 report on human rights abuses in Ukraine, Amnesty International wrote, “There is no adequate and fair asylum procedure in Ukraine, and its asylum system fails to comply with international law.”
Mr. Butkevych said that kidnappings were rare but that asylum seekers were routinely deported or extradited from Ukraine in violation of their rights.
“In general terms, Ukraine is not a safe country,” Mr. Butkevych said.
“For some people, especially those people who are actually wanted by their countries of origin, it can be dangerous.”
That certainly proved true for Mr. Razvozzhayev, a former amateur boxer and native of Siberia who has long been a close associate of Sergei Udaltsov, the leader of the Left Front, a radical socialist group that is at the core of the Russian political opposition.
Mr. Razvozzhayev’s lawyers say that after he was abducted, he was driven across the Russian border, held for nearly two days in the basement of a house, denied food and subjected to what has been described as psychological torture, including death threats against his family.
They said he was also forced to write and sign a 10-page confession, admitting to allegations first raised in early October in a documentary on NTV, a government-controlled television channel.
The film showed Mr. Udaltsov, Mr. Razvozzhayev and others, in what was said to be a meeting in Minsk, in Belarus, appealing for financial assistance from a political operative from Georgia, the former Soviet republic.
While they have admitted meeting with the Georgian, Givi Targamadze, Mr. Udaltsov and Mr. Razvozzhayev say much of the documentary was fabricated In recent weeks, the Russian authorities have opened yet another criminal case against Mr. Razvozzhayev, charging him with an armed robbery that occurred in December 1997 in his hometown, Angarsk, in eastern Siberia.
Supporters of Mr. Razvozzhayev said the added charges were an attempt to pressure him into confessing in the original case and testifying against others.
In October, when the political opposition held elections to choose a leadership council, both Mr. Udaltsov and Mr. Razvozzhayev were on the ballot.
But with pressure over the documentary intensifying, Mr. Razvozzhayev decided not to wait around for the results.
He filled a small plastic bag with personal belongings and left the apartment on the western outskirts of Moscow where he lived with his wife and their two children, heading for Kiev.
On VKontakte, a Russian social media site, he posted a note denying the allegations made in the NTV documentary and announcing that he was going into hiding.
“If in the near future I am arrested or if something bad happens to me, do not believe anything,” he wrote, “no matter what bad things they say about me.”
It is clear that he was afraid of being followed and also that he had no intention of returning to Russia.
Instead of taking one of the many direct trains to Kiev from Moscow or an even quicker direct flight, he took a circuitous route, first to Belarus, where Russians can travel without a visa, then from Belarus into Ukraine.
Arriving in Kiev on a Tuesday afternoon, he called Sergei Kirichyk, an old friend and the leader of Borotba, a Marxist group.
They met, along with other associates, at a kitschy, Soviet-style restaurant near the railroad station, a place with tasseled lampshades, carafes of vodka on the tables and old front pages of Pravda papering the ceiling, where Mr. Razvozzhayev contemplated an escape to the Czech Republic or Sweden.
That night he slept on a mattress in the Borotba office, an apartment overlooking Kiev’s opera house.
The next morning, Russian authorities officially declared him a fugitive and special-services police searched his Moscow apartment, as well as the home of Mr. Udaltsov, who was questioned and barred from traveling outside Russia.
In Kiev, Mr. Razvozzhayev stepped up his efforts to apply for political asylum.
On Wednesday night he went for a walk with a friend, Dmitry Galkin, a newspaper writer.
They met at a subway station near the headquarters of the Ukrainian central election commission.
“I didn’t know he was in direct danger,” Mr. Galkin said.
“He told me that he wanted to become a political refugee.”
As they walked along the darkened streets, they were sure they were being followed.
Mr. Razvozzhayev shut off his cellphone and ran away through a dark courtyard.
The next day he called the Kiev office of the United Nations High Commissioner for Refugees, where officials arranged for him to meet with a lawyer at 10 the following morning.
Anxious to get his application done, Mr. Razvozzhayev skipped breakfast.
So about 1:30 p.m., when his lawyer said he needed to make some calls, Mr. Razvozzhayev stepped out for a bite.
He did not come back.