Complex sentence: His Tribunal's President told him that Salim had been located in the Bagram detention facility, but that the Bagram authorities had not replied to the Tribunal's request for Salim's testimony.
Split into simpler sentences: His Tribunal's President told him that Salim had been located, in the Bagram detention facility. But that the authorities at Bagram had not replied the Tribunal's request for Salim's testimony.