As the US continues to keep suspected al-Qaeda members in legal limbo at its Guantanamo Bay detention centre, recent efforts to jail alleged Islamists in Germany by more conventional methods have failed spectacularly. This month, a German appeals court overturned the only conviction made in connection with the terrorist attacks on September 11, 2001. It was the latest in a series of setbacks for German authorities trying to prosecute individuals thought to have al-Qaeda ties. Germany has been a focal point in the global campaign against the group since investigators determined several of those involved in the attacks on New York and Washington lived in the northern German city of Hamburg. Mounir el Motassadeq, 29, a Moroccan suspected of aiding members of the Hamburg terror cell, was sentenced in February last year to 15 years in prison for being an accessory to commit 3,066 murders and a member of a terrorist organisation. But on March 4, Germany's Federal Court of Justice granted Motassadeq a retrial after a panel of judges ruled key evidence might have been withheld. 'It was really less Germany's fault and more the reluctance of US authorities to share evidence that botched things,' said Michael Byers, an international law expert at Duke University. Still, the decision to give Motassadeq a new trial came only weeks after the acquittal of Abdelghani Mzoudi, another Moroccan who had faced similar charges of supporting the Hamburg cell. The legal defeats have embarrassed German officials and are frustrating some anti-terror experts. 'Everyone knows they're both al-Qaeda,' said Kai Hirschmann from the Institute for Terrorism Research and Security Policy, referring to Motassadeq and Mzoudi. 'They should probably be in jail. But Germany's legal framework makes it very difficult.' Dr Hirschmann also said that although the Hamburg terror cell had focused attention on Germany's justice system, courts in most western democracies were struggling with similar problems. He pointed to the difficulties United States' prosecutors were having building a case against Zacarias Moussaoui, a French citizen thought to be an Islamic extremist who planned to take part in the September 11 hijackings. US officials also refused to allow Moussaoui access to al-Qaeda prisoners for his defence, leading a US judge last year to scale back the prosecution's case against him. 'This isn't just Germany's problem,' Dr Hirschmann said. 'It's a problem for the entire west.'