Mounir el Motassadeq's conviction on more than 3,000 counts of accessory to murder and membership in a terrorist organization was flawed because the lower court failed to properly consider the absence of evidence from a key witness who is in U.S. custody, the Federal Criminal Court ruled.
"The case is to be sent back to another panel of judges at the Hamburg court for a new trial and decision," presiding Judge Klaus Tolksdorf said in reading the verdict.
But he said, "The defendant el Motassadeq is certainly far removed from being clear of suspicion."
El Motassadeq, 29, is serving a maximum 15-year prison sentence after the Hamburg court convicted him in February 2003 of giving logistical support to the Hamburg-based al Qaeda cell that included Sept. 11 suicide hijackers Mohamed Atta, Marwan al-Shehhi and Ziad Jarrah.
Thursday's ruling is a new setback for German prosecutors after the same Hamburg court last month acquitted el Motassadeq's friend Abdelghani Mzoudi of identical charges for lack of evidence.
After the appeal ruling, el Motassadeq's lawyers said they would ask the Hamburg court to free the electrical engineering student from custody. El Motassadeq did not attend the session in the southern city of Karlsruhe.
El Motassadeq's lawyers argued he was denied a fair trial because the United States refused to allow testimony by Ramzi Binalshibh, thought to be the Hamburg cell's key contact with al Qaeda.
Binalshibh was captured in Pakistan on the anniversary of the Sept. 11, 2001 attacks and is in U.S. custody in a secret location.
The U.S. Justice Department has told the Hamburg court that Binalshibh is "not available." The German government also refused to turn over transcripts of his interrogations, saying they had been provided by the United States for intelligence purposes only.
El Motassadeq acknowledges knowing the hijackers but denies that he knew anything of their plans and maintains that Binalshibh could confirm his claim.
Mzoudi benefited from a statement presented by German investigators in which an unnamed source believed by the court to be Binalshibh said the only people in Hamburg who knew of the plot were hijackers Atta, Marwan al-Shehhi and Ziad Jarrah as well as Binalshibh.
Though that evidence was not considered in el Motassadeq's appeal, defense lawyer Graessle-Muenscher said it would "definitely" play a role in the retrial.
Without ruling on el Motassadeq's guilt, the appeals court said the lower court erred because it failed to consider whether the lack of direct evidence from Binalshibh should have influenced its decision.
A lawyer for relatives of Sept. 11 at both trials, Andreas Schulz, said Thursday's ruling "will certainly be met with incomprehension" by them.
The Hamburg court cited a mosaic of evidence including el Motassadeq's payment of tuition and rent for other cell members. That helped them maintain appearances of a normal student life in the city while plotting the attacks, the court said.
Federal prosecutors had wanted to see el Motassadeq's conviction confirmed, insisting that the Hamburg court made every effort to get Binalshibh's testimony. But experts believe a retrial is likely after critical questioning by the appeals judges at a January hearing.
El Motassadeq's lawyers also argued that al Qaeda hatched the Sept. 11 plot in Afghanistan and the hijackers trained to fly in the United States, so Atta's group did not constitute a German-based terrorist organization under laws in force at the time.