A MailOnline investigation into the sale of Syrian passports and other identity papers revealed the way ISIS fighters were able to sneak into Europe alongside genuine refugees.

The documents, described as 'real' by a police forgery expert, exposed the frightening ease with which terrorist sleeper cells were able to cross the continent to carry out the devastating attacks in Paris.

The Syrian passport found among the remains of a suicide bomber who blew himself up outside the Stade de France was identical to the one obtained by MailOnline in just four days.

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Exposed: The Syrian passport (pictured) found near the scene of a suicide bomb explosion at the Stade de France was identical to the one exposed by a MailOnline investigation which uncovered that ISIS fighters posing as refugees were using to sneak into Europe

Fake: For just $2,000, MailOnline obtained the same forged Syrian passports (pictured) being used by ISIS fighters to trick the authorities into believing they are asylum seekers

Trickery: The Syrian passport found at the Stade de France belonged to Almohammad (pictured), who registered as a refugee on the Greek island of Leros on October 3

'While we don't have the full facts yet it appears that a terrorist used a false Syrian passport to come into Europe among the refugees,' said Keith Vaz, MP, chairman of the UK's Home Affairs Select Committee.

He told MailOnline: 'This does appear to be what happened. This is deeply concerning.'

Finger print analysis of the bomber's remains revealed the man, who had falsely declared himself to be a Syrian named Ahmad Almohammad, 25, had entered Greece as a refugee on October 3.

He was among 198 migrants who landed on the island of Leros after crossing the Aegean from Turkey on a raft.

He was processed as a refugee by the Greek authorities who interview more than 1,000 migrants and refugees a day to establish their real identities and nationalities.

They took his photograph and fingerprints before giving him a document that enabled him to buy a ferry ticket to leave the island for Athens.

Almohammad left EU state Greece a few days later. He crossed into Macedonia and into Serbia where he was registered at the Presevo border crossing on October 7.

He continued north and entered the EU again when he crossed into Croatia. He was registered at the Opatovac refugee camp on October 8, before eventually travelling to Paris to commit mass murder.

The two other suicide bombers who detonated themselves outside the French national stadium carried false Turkish passports, it has emerged.

Arrival: After arriving on Leros from across the Agean, he was processed as a refugee by Greek authorities

Travel: A photograph of the ferry ticket (pictured) he used to travel from Leros to the Piraeus on the Greek mainland has also emerged

'MailOnline was ahead of the game with this information,' said Philip Hollobone, MP for Kettering, of the investigation which revealed how ISIS fighters were sneaking into Europe disguised as refugees.

He added: 'It's a very worrying development but with the very large number of refugees crossing to Europe it is inevitable that some terrorists will come this way.'

Mr Vaz, MP, said: 'When you have a mass movement of people there are always risks involved.

'It's clear that we must make sure that border security is at its best. We need to have the equipment to be able to deal with people at Europe's borders.'

It's a very worrying development but with the very large number of refugees crossing to Europe it is inevitable that some terrorists will come this way Philip Hollobone, MP for Kettering

And Philip Davis, MP for Shipley, told MailOnline: 'This should be a warning to us all. We should not be surprised that ISIS is using the easiest method to get into Europe.

'People who believe that we should let anyone into Europe who claim to be Syrian should reflect on the events in Paris for a few moments.

'Of course we want to help genuine refugees who are fleeing for their lives but we want to keep ourselves safe as well.'

A MailOnline reporter was able to buy a Syrian passport, identity card and driving licence from a fraudster in a Turkish border town in September this year.

The passport book was genuine, stolen from Syria when blank. The forger added the reporter's picture and gave him the identity of a Syrian man from Aleppo who was killed last year.

The other papers – the identity card and the driving licence – supported the false identity and gave credibility to a claim for asylum in Europe.

The documents were bought for $2,000 and were ready in just four days.

Probe: The fake passport book obtained by MailOnline - to expose how ISIS fighters are sneaking through Europe disguised as refugees - was genuine and stolen from Syria when blank

Forged: The fake passport, identity card and driving licence obtained by MailOnline were bought for $2,000 and were ready in just four days

The forger warned MailOnline in September that ISIS fanatics were using false identities to travel undetected across borders into Europe hidden among the tens of thousands of genuine refugees fleeing the devastating war in Syria.

As he chillingly put it: 'ISIS fighters are among the people going to Europe in this way. They are going to wait for the right time to become a fighter for ISIS again.'

ISIS fighters are among the people going to Europe in this way [forging passports]. They are going to wait for the right time to become a fighter for ISIS again Passport forger

An analysis of the Syrian passport bought by MailOnline by the German Police confirmed it was genuine.

Joerg Aehnlich, forgery expert of the Lower Saxony Criminal Forensic Institute, said: 'This is genuine, this is a real Syrian passport.'

The passport book MailOnline acquired is genuine, made from a batch seized from one of the many Syrian government offices captured by advancing opposition forces.

The forger explained that the militias fighting the forces of Assad prioritise government offices when they over-run a town. They know the value of the documents there and steal the empty passport books, papers and even the printers that are used to create identity cards and driving licences.

He said: 'Fighters – from the Free Syrian Army, Al Nusra, ISIS or whatever – they know the value of these documents. They take them and give them to us. They ask us to make new identities for them and their families so they can travel outside Syria.

'We do this for them and they leave us some of the books so we can sell them.

Deadly: At least eight terrorists killed more than 120 people in a night of unforgettable terror in Paris on Friday

Manhunt: Anti terror police enter a house in the Mirail district, Toulouse, last night when more than 150 similar raids took place throughout the country

'There are many people – Syrian people – who have lost their passports and identity cards because of the chaos of the war. They want new documents to help them in Europe.'

The manufacture of passports and identity documents began following the collapse of Syria's Assad regime.

There are many people – Syrian people – who have lost their passports and identity cards because of the chaos of the war. They want new documents to help them in Europe Passport forger

But the public service of creating marriage and birth certificates – and passports - for ordinary citizens who had lost their documents has been hijacked by criminals who will sell to anyone with money.

A Syrian with knowledge of the illegal trade told MailOnline: 'They understood that people needed documents so they helped them and got a bit of money for themselves.

'But now there are people who are only interested in the money.

'They don't care who they sell a passport to – even if they are terrorists.'

MailOnline embarked on this investigation after the scale of the trade in fake Syrian documents emerged in September.

German customs officials seized packages containing large numbers of blank Syrian passports.

Frontex, the EU border agency, reported an increase in the seizure of Syrian passports for although. They admitted they had no idea of the size of the problem.

Haunting: The forger who gave MailOnline a fake passport warned ISIS fighters were using false identities to travel undetected in Europe, mingling among thousands of genuine refugees (pictured) fleeing Syria

Hiding in plain sight: The forger said: 'ISIS fighters are among the people going to Europe in this way. They are going to wait for the right time to become a fighter for ISIS again'

German authorities have been overwhelmed by tens of thousands of migrants who are using fake Syrian documents to claim asylum, Mr Aehnlich revealed.

Bogus papers are also being used by economic migrants from other Middle Eastern states who know that a Syrian asylum claim will be met with sympathy following the civil war.

The death of Aylan Kurdi, the three-year-old boy pictured downed and washed on a Turkish beach in September, heightened demands for countries to take in Syrian refugees and propelled their plight to the top of the international agenda.

Germany alone is expected to take in a million Syrians this year and is putting other EU nations under pressure to sign up to a quota system.

The forger told MailOnline: 'Everyone wants to be Syrian now – because everyone welcomes Syrians.'

A record 5,809 migrants entered Hungary in one single day in September as countries across EU countries began to impose tougher border controls to stem the flow.

Sweden is the latest country to resurrect its national barriers to halt the arrival of migrants, following on from Germany, Austria, Slovakia and the Netherlands.

Hungary built a razor wire fence with its border with Serbia to stop migrants passing through its territory on their journey to the richer EU countries further north.

Route: Slovenian soldiers, whose country is on the 'Balkan route' taken by thousands of migrants heading for Europe, set barbed wire fences on the Slovenian-Croatian border near Rakovec

Precautions: Slovenian special police forces gather after been deployed in the disputed area near the Harmica-Rigonce crossing

However an EU leader has urged nations in the open-border Schengen zone to maintain passport-free travel, despite the refugee crisis and the Paris attacks.

European Council President Donald Tusk said: 'We must do all we can to keep Schengen intact and so any initiative that may lead to the re-establishment of borders within Schengen should be with-held.'

And he urged tighter restrictions at the EU's frontiers – principally Greece and Italy.