What Holdbrooks noticed during his time at Guantanamo is that most of the guards were miserable, including himself. They would abuse alcohol, porn and sports as a way to escape the pain deep inside. On the other hand the Muslim prisoners were content and smiling despite the abuse they were enduring. They were very attached to their religion and performed their rituals with devotion.
He was trying to understand how these men still believed in a loving God given the trials they were going through "I had all the freedom in the world, but I was waking up unhappy while these men were in cages, smiling and praying five times a day."
Holdbrooks started speaking to the detainees "I knew nothing about Islam prior to Guantanamo, so this was a complete culture shock to me. I wanted to learn as much I could, so I started talking to the detainees about politics, ethics and morals, and about their lives and cultural differences, we would talk all the time." One prisoner that Holdbrooks talked to a lot was Ahmed Errachidi: "We'd talk for hours and hours. We'd talk about books, about music, about philosophy: we would stay up all night and talk about religion.". Errachidi is a Moroccan who lived in the UK for 18 years and that the other prisoners called the General. US authorities accused him of attending Al Qaeda training camps but found no proof and ended up releasing him.
During this time Holdbrooks was also doing research on his own, reading the Quran, chatting with Muslims on the internet. He started to feel good about Islam. "The Quran is the simplest book in the world to read. It doesn't have magic. It doesn't contradict itself. It's simply an instruction manual for living." He saw the detainees as living proof that the instruction manual does work even in extreme situations.
Finally one day in December 2003, while talking to Errachidi he repeated the shahada, the statement of faith, and became a Muslim while still a guard at Guantanamo. he said "It was not easy praying five times a day without my colleagues finding out. I told them I had to go the bathroom a lot."