A CIA officer who oversaw the agency's interrogation program at the Abu Ghraib prison in Iraq and pushed for approval to use increasingly harsh tactics has come under scrutiny in a federal war crimes investigation involving the death of a prisoner, witnesses told The Associated Press.

According to The Associated Press, Steve Stormoen, who is now retired from the CIA, supervised an unofficial program in which the CIA imprisoned and interrogated men without entering their names in the Army's books.

The so-called "ghosting" program was unsanctioned by CIA headquarters. In fact, in early 2003, CIA lawyers expressly prohibited the agency from running its own interrogations, current and former intelligence officials said. The lawyers said agency officers could be present during military interrogations and add their expertise but, under the laws of war, the military must always have the lead.

Read more about the CIA officer and Abu Ghraib prisoner's death from The Associated Press