>> shami: yeah.taping his conversations. >> cooper: dabla deng spent three years pretending to be simpson's friend, and was paid $132,000 by the fbi. he taped more than 1,500 hours of their conversations and finally recorded him talking about traveling overseas to wage jihad. simpson lied to the fbi about it and got three years probation. >> shami: when he found out that this guy was spying on him, and taping him and then finding out that the government was doing that, i think something clicked in him. and the mosque we couldn't do anything. because we don't know what he did. >> cooper: he felt that the mosque had abandoned him? >> shami: yes. and he felt that a lot of people had abandoned him. and that's why he stopped coming to the mosque. >> cooper: he moved into this phoenix apartment complex with nadir soofi, who he knew from the mosque. soofi had just had a bitter break-up and the pizza parlor he owned was going out of business. it was here in this apartment that simpson and soofi began closely