Lawyer Alexander Popkov facing an officer guarding the way into a district police station in Russia's Winter Olympics host city of Sochi, turned on his phone camera and launched into a tirade.
People held in a city-wide round-up of illegal migrants walk in single file towards a district police station in Sochi on September 24, 2013
"I'd like to report a crime," he told the stoney-faced policeman. "You have dozens of people detained illegally in your courtyard."
Popkov has been trying to help people detained in a city-wide round-up of illegal migrants ahead of the Games in February -- many of whom are employed to build infrastructure for the event.
"It's a wide sweep, they detain everyone, and then start figuring out what to do with them," said Popkov, who offers his services pro-bono to a consultation centre set up by one of Russia's most prominent rights groups, Memorial.
"We work with migrant workers, but now we are forced to help all Sochi visitors, even Russian tourists", who have also been targeted, he said.
The raids started in September, when the governor of Krasnodar region, Alexander Tkachev, approved 60 "mobile squads" designed to rout illegal migrants.
"Not one illegal migrant should remain in Sochi two months from now," he told them.
Tkachev is a loyalist to President Vladimir Putin who has dipped into nationalist rhetoric on many occasions.
He has dispatched Cossacks -- a conservative community in the region that traditionally formed its own militias and was employed by the Tsarist regime on Russia's border with the Caucasus -- to team up with migration officials and police in checking every Sochi apartment where migrants might hide.
In one recent visit to the central Sochi police station, Cossacks in traditional garb flanked by men in migration service jackets along with police officers brought in two busloads of men, presumed to be migrants, over the course of just one hour.
Waiting 'like hawks'
Workers are rounded up in their homes, in the street, or just outside construction sites, and often spend at least a night in detention, disrupting work, said a representative of one construction company who came looking for a vanished Uzbek worker.
Large numbers of migrants from inside Russia and ex-Soviet republics are being employed by construction firms racing to finish Olympic-related building works on time.
"Anti-migrant groups wait by our site like hawks, and then detain workers as they leave," the company representative told AFP, who did not want to give her name.
"Two hundred workers would leave for the night, and in the morning 150 would show up at work. Where did 50 workers go? Nobody knows."
The Uzbek worker, who had all his papers in order, was returned to his employer after spending almost three days in the police station courtyard, where people have to go without food or a place to sleep.
The campaign has even affected Russian citizens on vacation in Sochi. Squads have kept them for several hours without explanation just because of their "ethnic" looks, one such detainee said.
"We showed them our bus tickets, our Russian passports, but they took us to the station anyway," said Zair Isayev, who was detained along with two friends -- one of whom spent nearly 24 hours at the station -- and nearly 300 other people crowded in the rain with no shelter.
"We were just in Sochi for three days of vacation, how can they treat tourists like that?" said Isayev, who lives in the southern Astrakhan region. "I'll never go to Sochi again, even to the Olympics. The Olympics can go to hell."
By law, the police can detain an individual for a maximum of three hours. After that, they must process documents recording the person's name and the reason for their detention.
But the sweep is conducted extrajudicially, said Popkov.
"It starts on a small scale. Now they are treating migrants this way, but later they will treat everyone in this manner," he said.
Several Sochi locals confirmed to AFP that door-to-door checks are conducted by a group that includes a policeman, a Cossack, a municipal official and a migration officer.
Squads take down the passport numbers and employment details of adults living at each Sochi address, and even the IMEI number of everyone's mobile phone -- a unique identifier that can be used to track down a phone even when it is turned off.
'Outrageous' detentions
Rights group Human Rights Watch this month warned the International Olympic Committee of the "outrageous" arbitrary detentions and deportations of workers, some of whom have not been paid in full.
But rights groups say further abuses are likely as Russia prepares to host the World Cup in 2018, another event requiring large-scale infrastructure development -- and labourers to do it -- in not one but a dozen Russian cities.
A new law signed by Putin in June allows an unlimited number of workers from abroad to come to Russia to build World Cup venues, exempting construction companies from the need to provide them with proper documents or labour contracts.
The loophole introduced by the new law will likely create "growth of human trafficking and coercive labour, including child labour", Russia's Labour Confederation warned.
"Employers, as represented by the state... have chosen the path of seeking profits, and increased exploitation of workers," the group said.