The odyssey of Mounir el Motassadeq -- convicted last August of belonging to a terrorist organization that included the planners of the Sept. 11, 2001 terror attacks in the United States -- through the German court system continued on Tuesday. This time to Motassadeq's advantage.

Germany's Federal Constitutional Court ordered the 31-year-old Moroccan released from prison where he had been serving a seven-year sentence following a conviction by a Hamburg court. As he left prison on Tuesday Motassadeq made no comment but he smiled as he got into his lawyer's car.

A statement from the court said that Hamburg judges had been wrong to order Motassadeq to be jailed because an appeal was still pending. "The fact that (no final) verdict was issued or that prosecutors have sought a higher sentence does not suffice to cancel the exemption from imprisonment granted earlier," the court said according to the Associated Press. Detaining the defendant "infringed on his basic right to liberty."

Authorities have long suspected Motassadeq of having belonged to the Hamburg terror cell led by Mohammed Atta, one of the suicide pilots in the Sept. 11 attacks. He arrived in Germany in 1993 and learned German in the university town of Münster before attending a technical university in Hamburg and eventually getting a job at the same school. He admits that he knew Atta in Hamburg but insists he knew nothing of his planned attack until seeing the events of 9/11 unfold.

Motassadeq became the first person convicted in connection with the Sept.11 attacks in 2003 and he was sentenced to 15 years in prison. But the conviction was overturned a year later, largely because of the US refusal to provide sensitive evidence or to allow testimony by witnesses such as Ramzi Binalshibh, a key suspect held by the United States. A retrial was ordered and the German prosecutor's office went back to the drawing board, later developing a meticulous case comprising some 3,500 pieces of evidence. And this time, the United States provided some documentation from Binalshibh interrogations -- but a personal appearance was not in the cards.