Abc's chief investigative correspondent brian ross picking up the story from here tonight. Reporter: Good evening, david. The question for the u.S. Now is, what does al libi know and how to... See More
Abc's chief investigative correspondent brian ross picking up the story from here tonight. Reporter: Good evening, david. The question for the u.S. Now is, what does al libi know and how to interrogators get it out of him? Counter terror officials say there is great value bringing to justice a man accused of helping kill 200 people. I think it's one for the good guys. Reporter: But the greater value may be measured more in what the 49-year-old al qaeda leader and computer expert can reveal about what is going on today. I think there's a lot he can say and I think there's a lot of gaps he can fill. Reporter: U.S. Officials say al libi had been under surveillance in libya for several months, so, the u.S. Already has a good idea of some of his current communications and connections and will use that to break him. That's called the we know all approach or the futility approach. In which you try to convince a detainee that you already know everything and there's no sense in withholding it. Reporter: Tony camerino is a former u.S. Senior military inter g interroga interrogator, who conducted more than 300 interrogators in iraq and teaches now how to break a terrorist. You can break anybody but the important thing is to build rapport, get information, try to figure out what motivates them. Reporter: Camerino says the fact that al libi's family saw what happened can also be used in the interrogation. We call that the love of family approach, where you emphasize that person's love to their family, the relationships with family members. Reporter: And among the big questions for al libi? Where is ayman al zawahiri hiding? What role, if any, did he play in the murder of the u.S. Ambassador in benghazi, libya? And finally, where, and when, is the next attack against the u.S. Likely to come? Of course, that is the biggest question. Brian back with us now. Just what can they do, brian, inside the interrogation room now? Is time their biggest weapon? Reporter: It really is. Waterboarding and the other so-called enhanced interrogation techniques widely considered to be torture are no longer used by the cia or anyone in the u.S. It's now a question of time. Playing mind games, trying to figure out what will get him to talk. Brian ross with us here tonight. Brian, thank you.
This transcript has been automatically generated and may not be 100% accurate.