Martha MacCallum: Steve Emerson joins us now. He's the executive director of the Investigative Project on Terrorism. Steve, good to have you here today. I know you have been talking to people on the ground there. Tell us what you think about this person who held these people hostage and what we have seen unfold here today.

Emerson: First of all, kudos to New South Wales police and the SWAT teams. They moved in with massive force, and they seem to have executed it very well. As I understand it they did take out the hostage taker, Sheikh Monis, who by the way we discovered – and I say we, my organization, the Investigative Project on Terrorism - just retrieved his website showing that he actually published a pledge to ISIS a month ago in which he offered to be a martyr for Islam. So there is no doubt that this was an ISIS-inspired act of terrorism. I can tell you based on my contacts through the night with my sources in Australian police and intelligence, time was ticking away as the debriefings of the early released hostages showed that Sheikh Monis was getting increasingly agitated. Number two, in the open line communications between him and the New South Wales police he was issuing more violent threats. Number three, there were indications that he was prepared to detonate bombs he said he had on him. He was wearing a vest. It was a question… about whether he was wearing a suicide vest, but as the day wore on and as the night wore into the early evening, there was a time ticking issue about whether they should move.

And they [the Australian commandos] felt at this point, as I understand it, that they had to move because he was prepared to do something quite drastic. So at this point they resolved it. But there is no doubt at this point that they had to move based on the intelligence they were receiving from the earlier debriefings of the hostages and from their own surveillance of what they were seeing through their snipers based outside as you saw it on the video. They had bomb squads ready to go in wearing the protective gear, Martha.

Martha MacCallum: They absolutely did and we saw several people run out. We're still trying to figure out the numbers of how many people may have been in there at the end. We saw four individuals come out on stretchers. And I should just let everyone know that we're waiting to hear some more information about their condition. And it's expected that the hostage taker, this Sheikh that you referred to who we've been talking about all morning, Sheikh Man Haron Monis, also referred to by you Steve as Sheikh Monis, interesting that he's Iranian in his background. That is not typically the ISIS connection would be a difficult link to draw there, but as you point out, on his web site he was clearly influenced by this group. As a terrorism expert, how do you draw the line from A to B or do you in this point?

Emerson: Well first of all ISIS has been unique actually in being able to draw shi'a and all types of Muslims to their battle because they are establishing a caliphate. He himself, Sheikh Monis, he was on the radar screen for ASIO– that's the Australian CIA - for years now because of one demonstrations he demonstrated in, communications overseas with Islamic terrorists, and his behavior in terms of what he has posted in social media, and his letter writing campaign of hate [to the families of fallen Australian soldiers in Iraq] . So they have known about this guy, but they couldn't arrest him [prior to this incident]. He was arrested several times in the past, but released. Was he known to be a potential terrorist? Yes. Could they have stopped it? Obviously not. This is the problem now of people who act alone without [being a part of ] a conspiracy [with] other people. So there's really hardly a way to interdict them, as Australia has done in the past 5 months. They have interdicted five major terrorist plots including one in which Islamic extremists and terrorists were going to behead Australian civilians in the heart of Sydney. So Australia has one the best records and the best intelligence services on Islamic extremists in their own country. But again, as we have seen in our own country when you have Nidal Hasan and other lone wolves, it's hard to stop individual lone wolf terrorists.

Martha MacCallum: It's a great point, and as you point out Australia has been very aggressive in terms of pulling passports of people that they have suspicion of. The United States has not done that. England has done that as well. This is a situation that we don't want to see repeated in other cities, but we know that ISIS has called for exactly that. So it's something that law enforcement across the nation has to be very vigilant about. Steve, thank you very much for all your information. It's great to have you with us today. Thanks.