The Senate hearing came on the heels of the Justice Department's decision in April to release pages of legal memos from the Bush administration as a part of a Freedom of Information lawsuit brought by the American Civil Liberties Union.
The memos argued that although someone subjected to waterboarding may experience the fear or panic associated with the feeling of drowning, the actual technique "does not in our view inflict severe pain or suffering."
The memos included an August 2002 legal opinion signed by top Justice Department lawyer Jay Bybee that provided the specific authorization for waterboarding that the CIA would use against three detainees -- Khalid Sheikh Mohammed, Zubaydah and Abd al-Rahim al-Nashiri -- in 2002 and 2003.
The memo, written just after the CIA had captured Zubaydah, noted that he had a fear of insects and advised the CIA that they could place the detainee in a box with an insect but that the CIA must "inform him that the insects will not have a sting that would produce death or severe pain."
Bybee revealed in the memo that the CIA was concerned because there was a "level of 'chatter' equal to that which preceded the Sept. 11 attacks" and that Zubaydah is "withholding information."
Bybee noted that the CIA wished to move to an "increased pressure phase," a phase Soufan said did not result in better intelligence.