Murat Kurnaz, who later spent years at the U.S. prison camps in Guantánamo Bay, Cuba, has claimed that two German soldiers came to interrogate him at a camp near Kandahar in 2002, and that one slammed his head into the ground.
Prosecutors in Tuebingen originally closed the case last May for lack of evidence, but reopened it in August after Kurnaz's lawyer identified two new witnesses.
They said in a statement Wednesday that the renewed investigation produced ''no further enlightenment'' on the alleged events.
The two new witnesses, who were held with Kurnaz in Afghanistan, were questioned by prosecutors in January and confirmed having seen German soldiers at the camp, prosecutors said.
However, it said there were differences in the men's testimony on details of what happened there. It added that one of the witnesses was ''almost constantly'' with Kurnaz but did not notice the alleged incident or any resulting injuries, and heard nothing about them.
Prosecutors said they consider the investigation closed, but noted that Kurnaz is entitled to ask for a review of the decision.
Kurnaz was detained in Pakistan in 2001, turned over to U.S. authorities and held at Guantánamo as a terrorism suspect. He was released in 2006.
The Defense Ministry has said that German soldiers questioned about the allegations recalled the presence of a German-speaker among prisoners they helped guard near Kandahar, but that the only contact they remembered was one soldier calling out to the man.
