An investigation by the BBC and the Organised Crime and Corruption Reporting Project (OCCRP) has uncovered documents which cast serious doubt on plans for the tiny Balkan nation of Montenegro to join the European Union.
Montenegro is an official candidate to join the EU and accession talks begin next month. This is despite concerns about allegations of political and financial corruption, which have led to the country being described as a "mafia state" - a claim which is forcibly rejected by the Montenegrin government.
The country has no currency of its own and has already unilaterally adopted the euro, despite concerns from Brussels. It is expected to be in the next batch of nations to join the EU after neighbouring Croatia becomes a member next year.
Montenegro's former Prime Minister, Milo Djukanovic, who is still president of the country's ruling party, was investigated by the Italian anti-mafia unit and faced charges over a billion-dollar cigarette smuggling operation based in Montenegro. Those charges were eventually dropped in 2009. As head of state, Mr Djukanovic had diplomatic immunity.
Now documents seen by the BBC raise further concerns about the man described as the "father of the Montenegrin nation".
An audit by accountants Price Waterhouse, carried out in 2010, raised questions about the running of the country's Prva Banka, or "First Bank", which is controlled by the Djukanovic family. The audit suggests that most of the money deposited at the bank came from public funds, while two thirds of the loans it made went to the Djukanovics and their close associates.
Miranda Patrucic, a Sarajevo-based investigator for the OCCRP, told the BBC that the Djukanovics and their associates "treated the bank like an ATM machine. A wonderful source of cash."
The handling of key privatisations, as the former Yugoslav country emerged from decades of communism, has caused widespread anger as Montenegrins have seen bills for services like electricity soar.
Thousands have taken to the streets, marching under yellow banners, accusing their political leaders of looting the country. They are demanding that Mr Djukanovic is put on trial.
Vanya Calovic, leader of an anti-corruption opposition movement, told the BBC: "Everyone is closing their eyes on the fact the country, government, executive, all parts of the power are linked to organised crime."
Milo Djukanovic, as Montenegrin prime minister during the Balkan wars, ordered the shelling of the ancient city of Dubrovnik in Croatia. Montenegro, which has a population of just 670,000, was an ally of the Serbs under Slobodan Milosovic.
It faced UN sanctions and turned to large scale smuggling of American cigarettes into Europe. They were distributed by Italian mafia, which is why the Italians launched their investigation. It found that Montenegro earned hundreds of millions of dollars a year from the trade.
After the break-up of Yugoslavia, Prime Minister Djukanovic became an ally of the West. In 2006, the United Nations recognised Montenegro as an independent state and the prime minister embarked on a series of privatisations. One of these was the sale of a small state-owned bank in which the Djukanovic family bought a controlling stake.
In 2009, Price Waterhouse Coopers were contracted to audit Prva Bank. The draft report was never published but the BBC has seen the document. It looked at the biggest loans and found that most were made to groups linked to the Djukanovics, and people linked to them.
Research by OCCRP has shown that they included companies connected with Stanko Subotic, who was also indicted by the Italian anti-mafia unit, and Darko Saric, who is a convicted drug smuggler, now on the run.
Montenegro's dramatic coastline and walled cities have made it a magnet for foreign visitors. In 2008, the tourist board was involved in an invitation to Madonna to stage a concert in the coastal resort of Budva. The BBC has seen paperwork which shows that the Djukanovic-controlled bank paid the fee, $7.5m (£5m), even though it was unable to pay its own depositors on time because of a shortage of funds.
The BBC approached Mr Djukanovic and Prva Bank to respond to the allegations against them, but neither has replied.
After the crisis in Greece there will be concerns about any lack of transparency in Montenegrin finances. The influential American publication, Foreign Affairs, described Montenegro as a "mafia state" earlier this year.
It is a charge echoed by Milka Tadic, the publisher of the independent local magazine, Monitor.
"If you have a former prime minister accused of smuggling, best friends with the mafia, how can you say we are not a mafia state?" she said.
In 2010, Mr Djukanovic stood down and was replaced by Igor Luksic, a 35-year-old English-speaking economist with an honest reputation. His appointment was initially welcomed by the opposition, but now they accuse him of failing to tackle the corruption of the Djukanovic era.
Mr Luksic told the BBC that claims his country is a mafia state are "ungrounded".
He said: "Montenegro belongs to a rare number of countries that have managed to make progress on every internationally recognisable indicator."
He accepts that his predecessor, Milo Djukanovic, is controversial.
"How could you not be after 20 years in Balkan politics?" he asks.
He argues that Mr Djukanovic is a friend to the West, and has steered Montenegro towards EU and Nato membership.
Last week the European Commission gave the go-ahead for accession talks to proceed next month. But it warned: "Corruption is still an issue of serious concern."
It said it would continue to monitor the country's progress as it approached accession.
The accession of the Balkan countries remains a key priority for those in charge of European expansion, and Prime Minister Luksic is hoping the talks will allow him to show the country is changing for the better. But for the government's critics, there first needs to be accountability for the alleged crimes and misdemeanours of Mr Djukanovic's two decades in power.
Watch Meirion Jones and Liz MacKean's full report on Tuesday 29 May at 22:30 BST on BBC Two, then afterwards on the BBC iPlayer and Newsnight website.