German authorities have covered up information that an elderly German citizen was tortured in a US secret prison in Bosnia in 2001, ZDF public television said on Friday.
It said official documents showed that the federal police (BKA) and the foreign intelligence service (BND) knew that Abdel-Halim K. was detained at the US military base at Tuzla in north-eastern Bosnia.
The man reportedly held both German and Egyptian nationality and had been seized in Sarajevo. Several German media reported about the case this week but did not mention the man's nationality.
Stern news magazine cited a German intelligence report as saying that BND and BKA officials had encountered the man while visiting the US camp in Tuzla.
The 70-year-old terror suspect needed 20 stitches to his scalp after he was hit over the head with a rifle butt, it quoted the report as saying.
One of the German police officials compared what he had witnessed at the US base at Tuzla in late 2001 to Serbian war crimes committed during the Bosnian war, it added.
The BKA and the BND have declined to comment on the media reports.
The German government has been accused of colluding with US agents in the detention of two other German citizens, one of Lebanese and one of Turkish origin.
A parliamentary committee probing the allegations heard this week that officials had "verbal contact" with one of the men, Murat Kurnaz, while he was held in Afghanistan.
The government of Chancellor Angela Merkel has sternly criticised the so-called rendition programme of terror suspects and has denied that there were secret US prisons in Germany, which is home to almost 100 US military facilities.