a plan designed and carried out by this man: abu musab al-zarqawi, the founder of isis. >> narrator: the secret history of isis began at the cia in the aftermath of 9/11. there was an urgent question about abu musab al-zarqawi. >> i was an analyst working on the team that was charged with evaluating whether or not al-qaeda and iraq had conspired together to conduct 9/11 attacks. >> narrator: at the agency's counterterrorism center, analyst nada bakos was tasked with learning everything she could about zarqawi. >> on the team, as an analyst, the big question was whether or not zarqawi was part of al-qaeda at the time. >> narrator: bakos began by piecing together zarqawi's life. >> zarqawi grew up in zarqa, jordan, which was also near a palestinian refugee camp. he was a tough kid in a tough neighborhood. >> narrator: poor and angry, it didn't take long for zarqawi to get into trouble. >> he was a thug. he was in and out of prison. he was a petty criminal. it was rumored that he had worked as a pimp. >> he was into drugs. he was into tattoos. you know, his friends in zarqa used to call