Conversation so far:
Where did Khalid El-Masri's torture occur?
Khalid El-Masri was flown to Afghanistan, where he was held at a black site and routinely interrogated, beaten, strip-searched, and sodomized.
Who was in charge of Khalid El-Masri's torture?
Khalid El-Masri was under CIA custody while being tortured.

Question: what group was being tortured?
Self-contained rewrite: What group was being tortured by the CIA?