Recently released Guantanamo-prisoner Muhrat Kurnaz claims German troops of the KSK (Kommando Spezialkräfte, similar to SAS) mistreated him while he was imprisoned in Afghanistan after being arrested in Pakistan.
Source:
http://www.spiegel.de/international/0,1518,443537,00.html
and
http://www.spiegel.de/international/0,1518,443493,00.html