What can a drug dog not smell

And the drug dogs never found anything? "No, the fabric is well wrapped up and then sprayed with a spray like that. It comes from Holland, is made of ammonia. Then the dogs won't smell anything." Over the years hundreds of cell phones and kilos of drugs have been smuggled into the prison in this way, Petrov says.

In a way, the predominance of the Russians ensures that there is little overt violence in prison. Territorial fights and visible conflicts are rare, say former inmates. The second rule in jail, Petrov explains: "Never solve your problems yourself." Fights only happen if the boss approves them. And even then there are clear rules: "In the cell, three firm blows. Either on the kidneys, stomach or heart. That is a lesson, most of them have learned it then." If there are outbreaks of violence, they are mostly hot-headed arguments, who are punished for it.

And the judicial officers? "They don't notice any of this. They are too few for that," says Florian Koch. You can't blame them. "They are nice, they can't do anything against the system either." If you ask officials and prison chaplains themselves, they confirm that. Nobody wants to express themselves openly. They don't feel safe either: "The Russians are so well connected, even outside. You're afraid that something will happen to you - and nobody will find out."

The state only has a chance if someone chats and betrays the community. Somebody like Alexei Petrov. But that's rare. "I knew this was my last chance," says Petrov, drinking the last sip of his coffee. He is now 32 years old, a handsome, intelligent man. "I thought about it for half a year." If he hadn't unpacked, he would have had to go back to prison for years. But now he has a wife, a child. "I am responsible," he says. "I have a new life."

But his old life always stays with it. Every day, the tattoos all over his body remind him of the contracts he made with his comrades. He pulls down his shirt. On the left breast is a tiger with an open mouth, about to jump. "That means: I never talk to an officer," he says and for the first time something like uncertainty flashes in his eyes.

Was his statement worth it? For him? For the state? Is there no longer a Russian mafia in the prison he was in? Petrov laughs. "Yes, of course. There are only a few people gone. But that's what others are doing now. The system always survives."