simply threatening torture
Torture would not have produced more useful results, and may have actually produced less useful results. Threatening it, on the other hand, seems to have worked.The issue with the CIA torture scandal is that you have a bunch of guys who may or may not know anything. These guys are interrogated, and, probably, disclose everything they know. Then, the higher ups at the CIA, acting on the authority of Cheney[1] and Bush[2] required that the guys being held—who may or may not know anything more or at all—be tortured to extract more information.
At this point, the guys being held who may or may not know anything are going to start telling their 'enhanced' interrogators anything they can in order to stop what's happening to them. It doesn't matter if it's real or fake.
[1] http://www.theguardian.com/world/2011/sep/09/dick-cheney-def... (and it's important to note that the Senate report on this subject revealed that torture had nothing to do with the discovery of bin Laden's location.)
[2] http://www.businessinsider.com/afp-bush-knew-about-cia-tortu...