Mohamedou Ould Slahi, a Mauritanian national, voluntarily turned himself in for questioning at the request of authorities in his home country in November 2001. The US then rendered him to Jordan, where he was interrogated for months. He was then shipped off to Bagram, Afghanistan and then on to Guantanamo in August 2002, where he has been held without charge ever since.
Slahi wrote about his torture in the US military’s island prison and the journey that led him there in his book, Guantanamo Diary, which is now out in paperback.
Human beings naturally hate to torture other human beings, and Americans are no different. Many of the soldiers were doing the job reluctantly and were very happy when they were ordered to stop. Of course, there are sick people everywhere in the world who enjoy seeing other people suffering.
But generally, human beings make use of torture when they get chaotic and confused. And Americans certainly got chaotic, vengeful, and confused after the September 11, 2001, terrorist attacks.