German prosecutors on said they had found no firm proof that a German-born Turk who spent four years in the US prison camp in Guantanamo Bay had belonged to a terrorist organization.
Investigators found no firm proof Kurnaz engaged in terrorist activities
The prosecuting authorities in Bremen in northern Germany said on Tuesday they had therefore dropped a long-running investigation into Murat Kurnaz.
The 24-year-old returned to Bremen in August after he was released from Guantanamo Bay following a deal between Washington and Berlin.
Kurnaz, who was nicknamed the Bremen Taliban by the German press, was arrested by US forces in Pakistan in early 2002 on suspicion of terrorist activities and taken to the notorious US military prison in Cuba. US investigators claimed he was an Islamist "enemy combatant" with links to al Qaeda.
In 2001, German authorities launched their own investigation to probe whether Kurnaz was a member of a terrorist group, a crime that carries a maximum prison sentence of 10 years.
Kurnaz has insisted throughout that he was innocent. On his return to Germany he accused the government of former Chancellor Gerhard Schröder of colluding with the US forces.