Identified and at least one of them linked himself to isis on social media. Tonight we learned from a source that the other would be terrorist spent a few years in pakistan in the 1990s. His father was pakistani and the sources describe his mother as white american. Well have more on what were learning about both gunmen in just a moment. Meanwhile, United States authorities are looking into whether the incident in texas has any link to International Terrorism as investigators try to piece together the timeline for the plot. Cnn justice correspondent pamela brown reports tonight. God bless america reporter the incident unfolded quickly in a dallas suburb at a controversial art exhibit showing cartoons of the Prophet Muhammad. Police say the two men pulled up to the parking lot in a darkcolored sedan. A patrol car blocked the entrance. A Police Officer and a Security Guard stepped out of the car. The attackers both in bulletproof vests jumped out of their car with Assault Rifles and opened fire. The unarmed guard was shot in the ankle. The officer, armed with only a service pistol, killed both gunmen. Under the fire that he was put under, he did a very good job. And probably saved lives. Were going to stop this right now. Reporter the controversial event inside was nearing an end when the shots were fired. Security moved the 200 people attending to a secure location. I need everybody to remain calm. Reporter none of the attendees were hurt. We were actually walking out and the officer starts blowing a whistle and telling people to get down. Reporter simpson is believed to have sent this tweet just hours before the attack using the texasattack. He also linked himself to a known britishborn isis fighter who later went on to tweet out details of the attack. Simpson was the focus of an fbi terrorism investigation for several years. In 2011 he was found guilty for lying about his plans to travel to somalia to engage in violent jihad. Pamela brown joins me now. So this guy, simpson, was clearly on the fbis radar. Did he slip through the cracks or are there too many people to monitor . Reporter well, its really a combination, anderson. I can tell you right now the fbi is scrambling to piece this altogether and figure out how simpson was able to leave his home in phoenix and come here and launch an attack that could have been much worse if it werent for the quick actions of that Police Officers. What we have learned, anderson, from a Law Enforcement official is that the fbi reopened an investigation into simpson not long ago. We know he was very prolific on social media. He had been in contact with known isis fighters. But i have been speaking to officials today about this issue of even if someone is under investigation, you cant have every Single Person under 24 7 surveillance, it just doesnt work that way. Its clear that simpson in this case was not under physical surveillance. Thats how he was able to make it here. Also, the online chatter, we know that he had tweeted hours before getting here that ominous tweet with the texasattack. Officials ive been speaking with say its frankly overwhelming with all of the chatter online, all of the different tweets, and so in some ways, you know, its one of their Biggest Challenges dealing with that, even with someone that is already on their radar, anderson. Pamela brown, thank you very much. Now, the two wouldbe terrorists lived together in an apartment in phoenix. Investigators have gone in, have taken out evidence. Meanwhile the members of a phoenix mosque that at least one of the gunmen attended say they are shocked by what happened. As i mentioned at the top of the program, new information is emerging about one of the men. Kyung lah joins me now with that. Reporter well, anderson, that man youre talking about is nadir soofi, hes the one we dont know quite as much about. But we are now learning from a pakistani source with knowledge about the family speaking to cnn, that soofi had a pakistani father and described his mother as white american. When they divorced, he went to pakistan with his father and his brother. He went to a prestigious elite private school in islamabad and then suddenly he left pakistan. Theres a gap of knowledge in what we know. In his mid30s, though, he came here to this apartment complex to be roommates with the other wouldbe gunman. It is through this busted it is through this busted doorway the wouldbe gunmen lived and hatched a plan. Nadir soofi grew up in pakistan and still has family there. Elton simpson, no other history of violence. Neighbors in their apartment complex saw nothing outwardly alarming from the two roommates. Ariel whitlock had been texting simpson who put his car up for sale. Im getting goose bumps thinking about it because i wanted to buy that car. Knowing that its on the news, i see it and its just blown up. I was going to purchase that car. You dont think like maybe hes going to go plot something and youre giving the money to help him go plot something, thats how i feel now. Its just crazy. Reporter neighbor tim raines never suspected. In fact he saw nadir soofi as a Good Samaritan who helped him in a medical emergency. You had contact with one of the men . One time about a year ago, he i came home and im walking up this and i had a heart condition. And i collapsed over here onto this stairwell. And he seen all that and he came over, offered me help. Reporter how do you reconcile that with a guy who drives to texas and shoots people . Oh, its easy. Everybody has a good side to them. If you see somebody hurting like that, youre going to help them. You know, i think he went to texas to shoot people for a reason. Reporter the reason appeared to be inspired by isis. On simpsons twitter feed he wrote the bro with me and myself have given bayah to muminen. A pseudonym for the leader of isis. His last tweet before the texas attack. But the first clues date back to that 2011 arrest. Talking to an fbi informant over years, Court Records show simpson wanted to go to somalia to fight. Recorded on wire taps saying if you get shot or you get killed, its heaven straightaway. Heaven, thats what we are here for so why not take that route . You try to make us become slaves to man . No, we slave to allah. Were going to fight you to the death. Attorney Christina Sitton defended simpson when the fbi arrested him. There are lots of questions now about whether hes someone who may have fallen through the cracks. Do you look back on the case and wonder the same thing . No, i dont. He was on probation for three years. He didnt have any violations. He didnt have any problems that i was aware of. I dont feel like he was ever a danger or ever someone that was going to be harmful. Perhaps he just got angry and did a really bad, terrible thing. Reporter nadir soofis Facebook Page reveals strong opinions but no call to violence. There is a 4yearold note asking for forgiveness. He asked allah for forgiveness for every sin. The intentional and unintentional, the secret and the open in public. Their plan so secret that the mosque president spent years with both men at services and never saw either as a threat. You have two members that they didnt show any signs of radicalization or any signs of even thinking about those things in that manner. So when that happens, it just shocks you. You know how good did you know these people . Thats a question that people ask themselves. I mean thats obviously a huge concern for investigators. Do we know what specifically investigators are zeroing in on right now . Reporter from what we could see, theyre trying to gather evidence to make that connection. You heard the surprise in all those peoples voices. How do they go from those men to lone wolf terrorists, would be terrorists. And so what we saw all day today are investigators combing through this apartment. They busted down the door. They have pulled out everything that they can find. Theyre going to comb through that, anderson, to try to make that link. All right, thanks very much. Joining me now is randy potts of the daily beast, who was at the event in garland, texas. Randy, clearly security was very good at this event. The fact that one officer with his Service Revolver was able to shoot two guys who were shooting at him with automatic weapons who had body armor is pretty extraordinary. Can you just describe what security was like as you entered the building . Yeah, security was extremely extensive. There were i went through two checkpoints just to park my car. Then just going from my car to the front door of the convention, i had to find a specific person, tell them my name. Then i went through a metal detector. By the time i got inside, i felt like the security was definitely sufficient. And once you were inside, what was the conference like . Did it seem like people were concerned at all for their safety . What went on . It didnt at all. The conference was very laid back. People were laughing, telling jokes, walking around, looking at the cartoons. So it did not feel like any sort of a threat was imminent at all. And i assume you couldnt hear or the people inside couldnt hear what was going on when these two guys drove up . No. Apparently there were a few people who were either outside the door or close enough to it that heard a few shots, but most of us did not. And how did most people react . So i was in the hallway with about five other people, and a guy in camouflage came running towards us shouting, getting inside the Conference Room immediately. We all went in there, the doors were shut and the room became actually fairly quiet. I think we were all listening to see if we heard anything outside the doors. In the video, there is guys in khaki, who look like they know what theyre doing. Are those private security or local police . It was a mixture, so im not sure which ones youre referring to. But there was apparently a s. W. A. T. Team. There was private security. Garland pd was there. Fbi was there was a lot of different people there. Im assuming its the s. W. A. T. Team were actually looking at. At one point in the auditorium, the lights went out, i understand . Right. After we had been in there about 30 minutes, all of a sudden the lights went out. That was really the only moment that i felt a little bit nervous or scared, because it wasnt planned. I dont know if it was just a fluke or a timer, but the lights went out for maybe 10, 15 minutes with only a few lights in the corners. And the actual event itself, what, there were cartoons depicting the Prophet Muhammad . Right. Those cartoons were posted around the room and, you know, before the conference started, everybody walked around looking at them and then there were several speeches. There was an award given for the winning cartoon, and then it was over. It was a very anticlimactic event during the conference itself. Randy, i appreciate you talking to us about your experience. Thank you very much. Randy potts from the daily beast. As we reported, at least one of these would be terrorists linked himself to isis in tweets before the attack. Were going to hear from peter berg next. Also tonight, in baltimore, questions about the charges against the six officers. Did the states attorney overcharge to keep more violence from happening . Thats one view youll hear coming up. 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Authorities are investigating whether yesterdays plot to ambush an event, attack an event in texas has any ties to International Terrorism. One of the wouldbe terrorists tweets to a known isis propaganda seems to suggest the attack was at least inspired by isis and not dictated by it, but the investigation is in its very early stages. Joining me now is Cnn National Security analyst peter bergen, author of manhunt the tenyear search for bin laden. Also cnn Law Enforcement analyst and former fbi assistant director, tom fuentes. This type of attack, the fact that it was attempted on american soil you say its unprecedented, but probably something we should get used to, no . I mean anderson, weve seen three americans already convicted before this of relatively serious plots to kill cartoonists, drawing cartoons of the Prophet Muhammad. One in pennsylvania, one in chicago and another american. Weve seen other americans also convicted of soliciting violence against people who are doing these cartoons and thats all in the last several years. So the fact that we actually saw violence actually now being done, i dont think that was that surprising. I think that Many Americans probably thought, hey, the events in paris or the events in copenhagen couldnt happen here, but the short answer is weve seen a number of these cases over the last several years. So this is not surprising. And, tom, were living in an age where somebody doesnt have to have any direct connection to a group like isis. They can simply just be ideologically motivated or inspired. Thats right, anderson. In this case youre looking at a couple of guys that apparently had zero training, was completely incompetent, inept attack. They managed to give a flesh wound to an offduty Security Guard and theyre armed with automatic weapons, Assault Rifles, and a single Police Officer with a pistol takes them out. Its unbelievable how poorly executed their plan, whatever plan that was, it had to have been something they hoped to achieve more than what they did. And or how good a shot this officer was. To do that under fire, its pretty impressive. Whats interesting is that you have, you know, Assault Rifle armed jihadists in paris and you end up with dead Police Officers who only have pistols or in some cases had nothing. Then you have the attack in copenhagen and you end up the same thing, Assault Rifle, policemen with pistols, policemen killed. Now you have garland, texas, where they have really just an exceptionally good plan to secure that venue, which they had to realize and did realize that it was extremely, you know, a target for jihadists. And now you have, you know, it shows the training, the discipline, the planning, and one Police Officer well trained is able to hold off the attack on that building. I can tell you a lot of my friends in texas will be saying right now dont mess with texas. I think theyre right. But, tom, the fact that this guy was very much on the fbis radar all the way back to 2006, i mean it seems to point out just how difficult it is to track these guys. Right. Ive heard you say that in every state, there are people like this and or people being monitored like this. Thats right. The director of the fbi, james comey has said that. We have investigations going on in every single state, multiple people, thousands of people. There are a million on the tide security watch list or terrorism watch list. So this is very common. Theyre trying to figure out when one is actually going to go bad rather than just the talk online and all that. They cant monitor every website or every person. You said at the beginning they were very much on the radar of the fbi. I dont think so. I think they were on the radar, but theres so many thousands on that radar, you know, its like trying to track mosquitos at a picnic. Peter, you and i have talked about this as well, this whole notion of someone not having direct contact necessarily, yet being inspired. Do you think i mean i know you think this is something were going to be seeing more of. We are, but theres a kind of good you dont want to say good news but building on toms point, i mean the police were well trained in garland and had the right response. But also the people that did the attack were not at all well trained. And so, yes, were going to see these lone wolves who are inspired by isis, but they didnt go to yemen and get training from al qaeda. They didnt go to the tribal areas in pakistan. You know, when you get that kind of training, youre more likely to execute successfully as we saw in paris, as weve seen with other cases. So, you know, if the future is a lot of lone wolves, its not a great future, but its a manageable future because theres a natural ceiling to what somebody without training can do. Even you know, in boston, the two brothers killed four people. It was a tragic attack. But it wasnt a National Catastrophe or anything on the scale of 9 11 and thats what were looking at going forward. And certainly, tom fuentes, were seeing a lot of Police Forces training themselves for what they call active shooter drills, which requires officers, first officers on the scene being the ones going in, not waiting for a tactical unit, not waiting for s. W. A. T. , but going in and getting the active shooter. Right. Try to eliminate the threat as quickly as possible. We just saw this a week or so ago in arizona where they didnt have the luxury of waiting for s. W. A. T. Teams and negotiators and psychologists and snipers to take out a man with a 3030 hunting rifle firing rounds in the middle of a street, a crowded street with strip malls on each side. An enterprising Police Officer took action and to