Barack Obama admitted recently that the only way he can close Guantánamo Bay, having pledged to do so within a year, is if foreign nations take in many of the inmates.

Yet the unmasking of Abdullah Ghulam Rasoul, former Guantánamo inmate 008, as a murderous and violent Taleban leader in southern Afghanistan confirms a trend that has emerged in recent weeks: significant numbers of freed detainees have returned to terrorism in a number of different countries.

In January Saudi Arabia said that it had arrested nine Islamist militants, some of whom were former Guantánamo inmates. Two other freed Saudis reemerged on a jihadist website railing against Britain, the US and Israel. One of them, Said Ali al-Shihri, is now the deputy leader of al-Qaeda’s Yemen branch. He is suspected of a role in a bombing at the US Embassy in the capital, Sanaa, in September, which killed 16.

How to shut the notorious detention facility is therefore not just becoming an increasingly complex political and legal burden for Mr Obama, given the fact that some of these freed detainees are clearly very good liars and very bad men. It is a problem for the rest of the world, particularly the European Union.

Several European nations, such as Portugal, the Irish Republic, Sweden and Germany, have said that they might take some of the 60 detainees who have already been cleared for release, but cannot be returned to their home countries because of the risk of mistreatment or torture. Yet what if some of them are violent extremists? Even though Britain has said that it will take no more Guantánamo inmates – after receiving ten British citizens, including Binyam Mohammed – those released to European countries could well be able to travel freely within the EU.

The Pentagon says that 61 former detainees have “returned to jihad”, although they have not provided evidence to back up that figure. Yet such a claim, and cases such as Rasoul’s, are already leading to European allies getting cold feet over taking in detainees, a fact that is acknowledged inside the Obama Administration.

There are about 250 detainees in Guantánamo. Between 20 and 80 are hardened al-Qaeda terrorists, including Khalid Sheikh Mohammed, the confessed mastermind of the September 11 attacks.

If Mr Obama gives them trials on the US mainland, what evidence could be used? Much of it has been obtained through coercion – the Bush Administration admitted that Mohammed was waterboarded – and there is no guarantee that a civilian judge would not throw such cases out.

Just the thought of transferring these inmates to the US mainland and upgrading military jails in Kansas, South Carolina and California has already triggered fierce, bipartisan opposition. On all these fronts, the case of Abdullah Ghulam Rasoul has only complicated Mr Obama’s hopes of closing Guantánamo. It is an issue that gets thornier by the day.

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