"We were driving up the hill on a single track road, and the police car was coming down it. They must have realised we were four cars in a row."
Slavi remembers vividly the day he and his fellow smugglers were caught. He has just served two and a half years in Bulgaria's notorious Boychinovtsi prison.
Each of the four cars was packed with Afghan migrants, like sardines, nine or 10 in each. The Bulgaria-Serbia border was only a few metres away.
"They turned on the blue light and drove right up to us. There was no way to escape."
The Balkan migration route is growing in importance again. Last September, according to the EU's border police organisation Frontex, this route overtook the Central Mediterranean route through Italy in numbers of irregular border crossings. Many cross through Bulgaria.
Some of Slavi's friends are still in jail in for people-smuggling. Eight men to a cell, 110 to a bathroom. The awful conditions of cold, damp, and hunger are, he says, the reason why he wants to warn people about the risks involved.
One friend, Ivajlo, was convicted of smuggling in Hungary, after he drove Afghans from Bulgaria on their way to Austria.
Imprisoned in Hungary, he had a stroke. Hungarian authorities sent him back to Bulgaria to complete his sentence and now he's in Boychinovtsi. Slavi alleges his friend can't get the medicines he needs and fears he will die there.
Bulgarian authorities did not respond to our request to visit the prison.
Slavi and his friend Svetlo take us to a basement in their home village of Septemvrytsi, in Bulgaria's Montana province, where we can talk privately.
These are the flatlands where the Balkan mountains slope down to the River Danube. Romania is on the far shore, Serbia across the land border to the west.
Smugglers further up the chain come here to recruit drivers, to take migrants across Bulgaria, from the Turkish border to the Serbian frontier.
It is also the best place to cross, either by boat to Romania, or walking across the fields into Serbia, to be picked up by smugglers there. Slavi was paid €50 (£43) per migrant, for the runs from the Bulgarian capital Sofia to the border.
How did he feel about making money from vulnerable people, I ask.
"It was good for the migrants who were escaping and it was good for me too. I don't see it like that now, but that's how it was then.
"We gave them something to eat. I think we were helping those people. They were looking for a new life, a better life."
It was mostly men but sometimes women and children. Miserable, thin, hungry people, lying on top of each other in the backs of cars with tinted windows. An Afghan "guide" would sit next to Slavi on the trips, their job to walk the migrants over the border.
The reason they got caught, Slavi says, is that they weren't earning enough to pay off the police, although he would have known who to pay.
They were at the bottom of the smuggling pyramid. The day they were caught, a "pilot car" driving ahead was not able to warn the others because there was no mobile signal.
His allegations of police corruption are reinforced by Pavlin Kodzhahristov, who was until last year the head of the anti-corruption unit in the Bulgarian interior ministry.
"There are lots of examples," says Mr Kodzhahristov.
"There was the officer from the border police who used to hide people in his car and bring them over from Turkey. Another provided misleading information to his police colleagues, sent them off on a wild goose chase on one part of the border while 40 or 50 people were crossing at another place."
In one remarkable case, a policeman turned himself in, convinced that the money he had earned was marked and that he was under surveillance. He wasn't, but by then he had burnt most of the money.
For the drivers, the risk of arrest is coupled with the growing danger of road accidents while evading arrest.
In February 2023, a truck was found abandoned at Lokorsko, near the ring road around the Bulgarian capital, Sofia. 18 Afghans were dead inside, suffocated.
Hedayatullah was one of the survivors. After more than a month in a coma, he recovered and was able to travel, legally, to Germany.
"I blame the smugglers and especially the driver because when the accident happened we were banging on the side but no-one came to help us, no-one came to open the doors," he told me.
"People are desperate to make this journey and at the same time the smugglers are making money and they promise lots of things but they don't keep their promises."
Slavi and Svetlo had nothing to do with that incident, but were appalled when they heard about it.
"I think the drivers were pretty dumb. These lorries are sealed. How could they not think of making a hole and letting some air in?" said Svetlo.
"Something like that could have happened to us and we are really grateful to God, because nobody died when they were with us."
Apart from highlighting prison conditions, the men say they also aim to dissuade other young Bulgarians from joining the smuggling trade.
Svetlo has also served prison time for smuggling and says he was recently offered €15,000 for a single run. He turned it down.
Both men have now gone clean.
"It wasn't easy for my wife while I was in jail," Svetlo says, "because I'd lied to her about my work, where the money was coming from. And she was left alone with young children."
