Bulgaria is under pressure to tackle organised crime ahead of entry to the European Union. One of the crimes mafia networks are involved in is the trafficking of pregnant women to sell their babies.
Yanna Dobreva Yordanova is 23 years-old, heavily pregnant and deeply distraught.
She sits in a bleak hospital ward in the small town of Lamia in central Greece with three other pregnant women at her side.
They are all from Bulgaria and all have the same story to tell. "We came here to work," says Yanna, "Slavka sent us here." But there was no job.
Instead the four women were held in a squalid flat in Lamia by a criminal gang waiting for them to give birth. The gang planned to sell their babies to local Greek couples potentially earning up to £20,000 (30,000 Euros) for each child.
"I was so miserable... and so stressed that the baby kept turning around inside me," says Yanna of her two-week ordeal locked inside the flat.
Her keeper was a man called Alexander. "One of the other girls heard Alexander on the phone talking about selling our babies," she says, "if one of us gave birth, he would sell the baby immediately, give us up to three thousand euros and get rid of us."
Realising they had to escape quickly, the women managed to get onto a balcony and shout for help.
The police raid which followed was just one of a series across Greece in recent months in which more than 20 suspected baby-traffickers and prospective Greek buyers have been arrested.
Yanna and the three other women rescued from the flat in Lamia told their story to the police and were soon able to return home to Bulgaria.
Despite reluctance from Greek and Bulgarian officials to help us find them, we eventually tracked them down to the Black Sea port of Burgas in eastern Bulgaria, one of the wealthiest regions in the country.
The Roma community in Burgas lives in poverty
Like the majority of pregnant women trafficked from Bulgaria, they are members of the Roma or gypsy community which makes up around five per cent of the Bulgarian population.
We found Yanna living in a tiny single-room home - more shack than house - in a squalid Roma ghetto not far from the centre of Burgas.
More than three thousand people live in the ghetto, the vast majority unemployed. Families of up to ten people here survive on less than £4 a day (5 Euros).
Yanna who is still pregnant, is more vulnerable than most. She already has two young children to look after and no partner. He recently left her. Little surprise then she was recruited earlier this year by the woman called Slavka who came round offering her a lucrative job in Greece.
"I was told I'd earn up to 45 euros a day if I took the job in Greece. What do you think I should have done? I decided to leave my children with my neighbour and go and earn some money. But I was lied to. "
Newsnight decided to try to track down Slavka and put these allegations to her. We had heard she came from the Roma community in a nearby town called Kameno.
Initially everyone we approached there denied knowing her. But eventually one man gave us an address telling us to look out for a house that stood out from the rest. In the midst of a grimy, non-descript street the large, brash building was unmistakable.
We found there an ordinary looking middle-aged woman surrounded by her daughters, who answered by the name of Slavka. Reluctantly she spoke to us at the front gate.
Slavka denies she is involved in trafficking
She vehemently denied the allegations that she was the recruiter for a baby-trafficking gang saying she'd never heard of Yanna.
But she did admit her house had been raided by the police and her husband taken away on charges of baby trafficking.
Later the police confirmed to us that she is under investigation for allegedly recruiting and transporting pregnant women to Greece.
Cracking the mafia gangs involved in the sale of babies abroad is not easy for the Bulgarian police. Baby trafficking was only made a crime in 2004 and the maximum punishment is just two years in prison.
Although the police say they are now having some success after launching up to eight major investigations nationwide, senior officers admit the cases they hear about are probably only the tip of the iceberg.
"It's a difficult crime to tackle successfully because it's an invisible crime," says Commissioner Kupen Kupenov, head of the regional organised crime unit in Burgas.
"If the women who are victims don't come to us, then we don't know about it because it's committed in another country."
The traffickers know they're tapping into a lucrative market in Greece where demand is high for the purchase of babies.
Greece has one of the lowest fertility rates in the EU in part because many couples are leaving it too late to have children. If they decide to adopt, the process is so complicated and bureaucratic it can take years.
Experts estimate they are currently 500 couples who have applied to adopt just 54 babies across the country. Many are therefore tempted to forget the legal adoption process and search instead for a baby to buy.
We eventually found one Greek woman who was willing to speak to us anonymously about her experiences dealing with the baby traffickers.
"The lawyer said it would cost eighteen thousand euros and he'd take care of all the legal paperwork. He would only let us know two or three days before we would actually get the baby and we would have to be ready. It was very fast - either you said yes or you lost the baby. In some ways it was shocking."
Eventually she pulled out of the deal because she wanted a one-year-old child not a new-born baby so she could be sure it was in good health.
It's evident that Greek lawyers, doctors and mid-wives have linked up with the Bulgarian traffickers to provide a seamless service to profit from the desperation for children in the country.
And according to the woman we interviewed what's particularly disturbing is that many ordinary people are well aware of this illegal trade but are turning a blind eye.
Richard Galpin's investigation can be seen on Newsnight on BBC Two (in the UK) and live on the Newsnight website at 2130GMT/2230BST on Tuesday 18 July 20056