Germany's second trial of a suspected September 11th conspirator is expected to offer more evidence about the Hamburg al-Qaeda cell that led the hijacked airliner attacks in 2001.
Mr Abdelghani Mzoudi, a 30-year-old electrical engineering student from Morocco, is charged with 3,066 counts of aiding and abetting murder, and membership of a terrorist organisation.
If found guilty, he faces the same 15-year jail term the Hamburg court handed fellow Moroccan Mounir El Motassadeq in February for his part in the plot.
Prosecutors allege Mr Mzoudi, like Motassadeq, handled money for a hijacker and got paramilitary training in Afghanistan. Mr Mzoudi will face a five-judge panel in the same steel-doored Hamburg courtroom where Motassadeq was sentenced.
However, unlike Motassadeq, who unwittingly incriminated himself with testimony that included an account of a trip to an al-Qaeda camp in Afghanistan, Mr Mzoudi will not testify, a move lawyers say may make the prosecution case harder to prove.
Germany launched a massive investigation into militants among its three-million-strong Muslim population after the September 11th attacks exposed it as a haven for the plotters.