Nightclub. More than 50 others were wounded. Many of them critically in what the president called today an act of terrorism and hate. Just after 2 00 this morning it was last call for drinks at the pulse nightclub, popular among the gay community, when sounds of gunfire rang out above the music. A lone gunman, 29 year old mar mateen made his way into the crowded club and opened fire. Oh my god, dude. Pelley a massive bar age of gunfire was exchanged with Law Enforcement and piecerred the predawn quiet near downtown orlando. Today president obama said the entire country stands with the people of florida. Today as americans we grieve the brutal murder, a horrific massacre of dozens of innocent people. We pray for their families who are grasping for answers with broken hearts. Pelley armed with an ar15 semiautomatic hand rifle and handgun, mateen was also wearing what police say could have been an explosive device. An Orlando Police officer working scooter at the club engaged the suspect with gunfire and it quickly turned into a tense hostage situation. This mother came looking for her son. I dont know where my son is. No one can tell me where my son is. If hes been shot, no one knows. But they told me there are fatalities. Pelley minutes later the club posted this message on facebook with a dire warning. Every one get out of pulse and keep running. Witnesses say people ran out between bursts of gunfire or dove for cover. This text message was written by a man hidden in a bathroom who believed he only had moments left to live. Mateen called 911 to pledge his allegiance to isis. There were the 911 calls in which there was conversation between the subject and Law Enforcement representatives of 911 dispatchers. That has become federal evidence. It was its my understanding, have i not personally listened to them, but it was general to the islamic state. Pelley Orlando Police used stunned grenades and armoured vehicle to enter the building. Three hours after the mayhem became a swat team engaged in a sustained gun fight, by 5 53 a. M. Orlando police said the shooter was dead along with 50 others. 53 were taken to local hospitals. Many of them in Critical Condition. The injured were carried out and transported by any means available. One officer was slightly wounded after he was hit in the helmet with a bullet. His kev lar helmet saved his life. Fbi and law enforce. Remain at the scene scourk for evidence. The gunman was born in new york and lived about a hundred miles southeast of here in fort piecer, florida. He worked as a Security Guard and he had drawn the interest of the fbi more than once before. Our National Security correspondent jeff pegues has more on on the suspect. Reporter Law Enforcement sources say the gunman o par mateen called 911 during the mass shooting. In the call to a dispatcher he stated his name and pledged his allegiance to isis. While he was not under investigation at the time, Officials Say mateen had been on Law Enforcements radar at least twice in recent years. Mateen was a u. S. Citizen born in new york to afghan parents. He was living in fort piecer, florida, and has been married. In 2012 mateen attended the handle which is an annual pril grammage to mecca in saudi arabia. A year later in 2013 the 29 year old turned up on the fbis radar for the first time. Coworkers said he had made inflammatory remarks about terrorist ties. The fbis rod hopper is leading the investigation. The fbi thoroughly investigated the matter including interviews of witnesses, physical surveillance and records checks. Ultimately we were unable to ver fie the substance of his comments and investigation was closed. Reporter in 2014 he came to the fbis attention again, this time because of ties to the first known american suicide bomber in syria. That man blew himself newspaper 2014. After that investigation, mateen was cleared again. We determined that contact was minimal. And did not constitute a substantive relationship or a threat at that time. Reporter mateen had been working as a Security Guard and with no record within the last week, he was able to purchase a handgun and the ar15 Assault RiflePolice Believe he used to kill and injure more than a hundred people. The attack appeared well planned. Mateen chose a soft target with few exits for his potential victims to escape. He exchanged gunfire with at least 14 Police Officers before he was shot to death. Scott, in that 911 call mateen made a reference to this tsarnaev brothers who carried out the boston am booing. The fbi has now taken those 911 tapes and has begun to dig deeply into mateens life and friendships. Sources tell us that he was not on any terror watch list. And so far there is no evidence that his actions were directed by isis but the 911 call suggests that he was at least inspired to act by the group. Earlier i spoke with former cia Deputy Director mike morell. How important is this 911 call . It says to me that this is absolutely an individual who was inspired by isis. Why . Because he said it, right. He said i pledged allegiance to isis, right . That is the act of becoming a member of isis, says to me he was radicalized. He was radicalized by them. Says to me this is an act of terror. Says to me this is the largest act of terror in the United States since 9 11. Reporter is it important for Law Enforcement to determine whether this was inspired or directed. Absolutely. Reporter and why . Significant difference between the two. Strategically and tactically. So strategically, the demonstrated ability of isis to reach inside the United States and direct somebody to conduct an attack is huge for their stature, huge for their followers. A very Important Message for them. Tactically, their able to reach inside the United States and direct one person to attack, means they can do two or three. Weve been talking, you and i in the last year, about Something Like this happening. And the almost certainty that it was going to happen. Its going to happen again, right . Orlando is not the last one. So more of it is going to happen. And there will be a debate, right. There will be a political debate about how much of our privacy and Civil Liberties do we give up to enhance our security. Reporter investigators also arrested a man in california who was armed with an Assault Rifle. They believe he was on his way to the gay pride parade in los angeles. Scott, at this time there is no apparent link between that suspect and the attack in orlando. Pelley Homeland Security correspondent jeff pegues in the washington newsroom tonight, jeff, thank you very much. We are just gunning to learn the names of a few of the victims. We just have a few names out of the 50 who are known to have died. They include eric ivan ortiz rivera. Peter gonzalez cruz. Edward so theomay diszor, jr. Stanley Luis Omar Capo and Juan Ramon Gu ilmo. A short time ago hi a chance to speak with one of the eye witnesses. Lets hear what he had to say. Sean, you were at the club this morning. What did you see . Happy faces. Everybody was having a good time, actually. And then next thing you know, it was like mayhem. I was in the back part by. I was in the back patio part outside, walking back with my best friend and another friend and they were walking in front of me, someone stopped to say hello. I hadnt seen them in awhile. I stopped. They kept walking. Next thing you know i hear bang, pop, pop, pop, pop, pop. And people were scaryting, running around. I didnt know what to do. Im looking for my friend. I kind of curled up in a corner for a second. Then i jumped over the back wall, that everyone was trying to get out. I jumped over and kept running. As much as i kept hearing the gun shots i kept running because i didnt know which way they were coming from. They sounded close, they sounded far, they sounded close, they sounded far. It stopped for about two seconds and then yeah. I ended up going underneath someones truck until it got done. Until some kind of calm. Because it was mayhem. You got under somebodys truck. Across the street. I went across the street to the wendys, there are houses and i went behind there and just, i tried to knock on someones door, to get 911 called. They called but no one was answering so it seemed like the shots kept on getting closer. How long did you hear gunfire, would you say . Honestly my mind was so gone by that point, probably a good minute, a good two minutes. Like inside and out, running away, a good two, three minutes. It just seemed like it wasnt done. It stopped for a few seconds like he was reloading or whatever, im not sure. So it stopped for a couple of secondses and started all over again. Yeah. What were you seeing and hearing at that moment . Screaming, yelling people that were wounded, just to get them out of the way. Sorry. I have never been so scared in my entire life. Pelley weve seen pictures of people just picking up those who were wounded and running them down the street to the hospital which say couple of blocks away. I saw some people doing that. They had the fire department, ambulances and people were doing it themselves. People when they came out, they scarted. I went straight across. Some people went to the right or left, some people went that way and came back this way. My best friend, we got separated. He was inside. He was one of the people, he got shot and apparently he got taken out. Someone dragged him out and got him to a ambulance. That is when i got in touch with him. Hes at the hospital. Another friend of mine was inside as well. Were looking for him, no one has heard from him, his family has been calling. We havent gotten in touch with them. Everyone is really, really worried right now. Pelley your friend who was taken to the hospital, how is he . He was in surgery last time that i checked. As far as i know hes done pretty well but he was hit pretty bad. I know two times in the back. And he got tramp eled over sew also broke his leg. And thats just one person. There were people outside, i couldnt even imagine to see what is on the inside, to be honest. I just know that its bad. But people were coming out. The ones close to me, were coming out. I feel bad there were so many people. Pelley as the Police Arrived you were stinld the truck. What did you see. I got out. Truck, because they were coming out. They were trying to get us in the same area behind the wendys and seven11. They had us surrounded. They were still looking for the person. They didnt know whether the person had gone, whether he was still inside or whatnot. We really didnt know what to think. We had no idea if there was more than one person, if there were people running around. The way the gun shots sounded it sounded like they were coming everywhere. One time it sound like over here, closer, farther away. I was literally on my phone, i was crying and trying to call my friend and nobody seemed to be getting through to anybody. It was the most nerveracking. Pelley didded gunman say anything that you could hear. I wasnt inside. I was outside on the patio. So i never heard the gunman or heard him. I just heard gun shots it went from having a fun time, music playing to three, four gun shots, music stopping and all you heard was gun shots, screaming and tables knocking over and people jumping, people screaming inside, trying to get outside, more gun shots. Im sorry. Pelley did it seem like it was ever going to end . No, it didnt seem real actually. I cant say it would never happen to anybody. I mean it has but if is very sad i dont know. It shouldnt be that type of hate. Sean, thank you so much. I appreciate you. That was difficult but people need to know what happened. Im so grateful. We cant tell the story unless you tell it for us. Thank you very much. Pelley eye witness and survivor sean has been estimated today that as many as 200 people managed to escape the club uninjured. Coming up next on this special edition of the cbs evening news, from more orlando, florida, why lone wolf attacks seem to be so difficult to stop. The terror attack here in orlando, florida, is proof once again that a man with a gun and a heart filled with hate is almost impossible to stop, Chris Van Cleese has more. As omar mateen mowed down patrons of the pulse nightclub, orlando joined a growk list of American Cities shattered by violence of a lone wolf style attack, inspired by hate, be it against a group of people or inspired by a group like isis. Orlando police chief. Our officers put themselves in harm away and risk their lives for the people and patrons at pulse. Lone wolf attacks have happened again and again,as year a husband and wife killed 14 rat an office party and five Service Members were targeted by a single shooter in chattanooga, tennessee. Has an quilled 14 at fort hood. All claimed to be inspired by islamic terror groups. A 2013 study looked at 63 attacks over a six year period and found 90 of the cases where the perpetrator was known was the work of one or two people. The overwhelming ma jolter were men and nearly 60 involved fire arms. This could happen anywhere in our world. Certainly anywhere in america. There are weapons available. This is exactly the thing that isis calls us to. It is a siren song. They want this sort of victory, that they can claim for themselves. And the more carnage, the better. Ron hosskoa is a former assistant dreblger of the fbi. He says since 9 11 theres been a huge focus on disrupting terror plots but the lone wolf is alot harder to spot. One person who is sitting in front of their computer out in Middle America thinking and looking and were waiting for their fuse to be lit, how do you get to that person . How do you predict that person . How do you defeat that person . Reporter complicating the effort to find these people, scott, hossko says every time there is one of these tragedies it becomes a blue print to a wouldbe attacker. Pelley kris van cleave reporting, thank you, chris, and in a moment, senator marco rubio of florida will stop by here to tell us more about what theyve tell us more about what theyve learned. Pelley back now from orlando, floor darks a short while ago we had an opportunity to talk to florida senator marco rubio after he had visited the crime scene. Senator, youve been over to the crime scene. I wonder what you saw there. It was horrifies. Obviously i dispt go in, investigators were coming outside, there were people there and relatives still calling their loved ones. It is just a terrible scene. Pelley when you go over there you hear telephone rings, people trying to call. Law enforcement, there are families calling their loved ones, they havent heard from them, they are hoping someone will answer. On the human scale, you think about the people that survived this and the ones still in the hospital and the ones that didnt that will need a lot of counseling and help with what they saw. This sounds luke a combat zone. Pelley what you have been told about the suspect . The federal authorities so far said pretty much what i know, that is an individual born in new york, raised in the u. S. , u. S. Citizen. Pelley the fbi was alerted to him in 2013 and 2014. He made some statements to people that seemed sim pathetic to radical islam. The question will be asked, why didnt the fbi do anything then. But give me the perspective on that. Well look into it. The Intelligence Committee whether conduct oversight into the process that went into all of this. But making statements alone is not enough to arrest anybody. This has all the markings of what is called a lone wolf, a home grown violent extremist after taking action after being inspired to do. So that is a growing threat in this country we have known about for awhile. Pelley senator, thank you so much. Im grateful to you. Im grateful to you. Back from orlando in just a moment. Pelley back now sphr orlando, florida. Families here are going through an agonizing wait, only a very few of the 50 people known to have been killed have been identified so far. More than 50 others are in the hospital, and many of them are in Critical Condition after surgery. Omar mateen, the gun mng who opened fire in pulse, a gay nightclub was american, born to afghan parents. He was killed in the shootout with police. He called 911 duringed attack and pledged his loyalty to isis. Though it is not at all clear at this point whether he had any direct contact with the group. For some of you, we will be leaving, but for other cbs stations, we will continue with this special edition of the cbs evening news from captioning sponsored by cbs pelley massacre in orlando. Oh my god, people are getting shot. This was an ak of terror, and an act of hate. Pelley a gunman opens fire in a gay nightclub. There were bodies, people that were wounded. Just to get them out of the way. Pelley at least 50 are killed in the deadliest mass shooting in u. S. History. Many more are wounded. I dont know where my son is. No one can tell me where my son is. If hes been shot, if hes dead no one knows. Pelley isis claims responsibility. The individual has been identified as omar mateen. We need to support each other. We need to