>> exactly. i just spoke with a senior official, there's a great amount of resolve to get to the bottom of this, but also i sensed great sadness as well. i'm being told that homeland security secretary jay johnson is in the office right now as we speak trying to get information. you can expect in the coming days as they get more information for this to be expanded out throughout law enforcement and the country to give them a sense of how this went down. how this suspect attacked these people. so that best practices can be learned. again, we don't know the specific intent here. terrorism is being looked at. the social media angle is being looked at. but this notion that isis has been using social media to inspire people on a daily basis to do something, troubled souls as the fbi director calls them, has been a simmering concern. now with san bernardino and if this turns out to be somehow inspired through social media, it is a concern that we will see

this more and more often, george. >> that is the danger. that is the fear. pierre thomas, thank you very much. a little after 11:30 on the east coast. we've been reporting all morning long on this horrific deadly shooting in orlando, florida. started to unfold after 2:00 a.m. gunman enters, shooting with on a automatic weapon. three hours later, 50 dead, 50 people injured. worst terror attack in the united states since 9/11. lauren lister has been on the scene all morning long. good morning. >> reporter: good morning, george this is where it all happened. this street now, a small police presence. a block and a half down, you can see the sign for pulse. that's the nightclub where fun turned into terror around 2:00

a.m. we heard all of this from officials today about how it went down the we responded on the scene at about 4:00 a.m. this is when we met the first eyewitnesss. one of them you heard from earlier, chris hanson, describing how he heard shots, saw people falling around him. he crawled out the door. one thing he told me, he didn't have a chance to tell you, he said he saw authorities in the parking lot tagging victims according to the severity of injuries, presumably prioritizing care was his belief and understanding. we also spoke to an eyewitness around that time who said he was communicating via text message with someone in the nightclub, in the bathroom locked in there who had been injured. at that time we didn't know this was still an active situation. we then learned at 5:00 a.m., we heard an explosion. we heard a boom. we were wondering what it was. a few minutes later authorities posting to social media that it was a controlled explosion. we know that was the time when

they decided they were going to get involved in this hostage situation and rescue those hostages. this is when they said they used some kind of explosion, went in and shot down that gunman. the s.w.a.t. team taking him down. that happened and he was confirmed dead by authorities at 6:00. 5:15 a.m., we heard a barrage of gunfire. this is around the time that a firefight may have been going down between the s.w.a.t. and the gunman. we know the gunman was armed with an ar-15 rifle. shortly after that, we were just -- this area was just -- i'm sure you've been showing video, was filled with police officers. the fbi responded. we saw bomb units. we saw canine dogs sweeping this whole area. this was a very active scene. ambulances were rushing people to this hospital, which is just over my shoulder.

this is the medical center that has treated, according to their social media, around 50 patients. this is where also family and friends have been showing up to find out any information about their loved ones. people like the mother we just heard from earlier who is so heart broken and distraught because she does not know what the status is of her son who was at this nightclub. that's the latest on the scene. one thing i can also tell you, earlier we talked about how we saw -- around 7:30 this morning when we were learning this information about what happened from this press conference, we saw a line of people walking down this street behind me. a half block away, a small street, getting on to buses and driving down to downtown orlando. the eyewitness i spoke to said that's where they were taking people who escaped the club. people who had gotten out, were not hostages, were able to run away after that gunman entered. that's where they had been held for hours until 7:30-ish when

they were boarded on to the buses and taken to downtown orlando. they were having all of the people in the nightclub go to police headquarters to get the information that they could. that's what i can tell you from this scene right now. >> great reporting right there, lauren. thank you very much. another eyewitness who is there, josh mcgill joining us on the phone right now. i know you were inside the club and helping to tend to victim? >> i sure was, sir. my two roommates and i were closing up with our tabs, last call for alcohol was called around 1:45. so we had about 15 minutes, you know, to finish a drink, gather everything. around 2:00 is when we heard the first initial gunshots. we were in the very far corner of the main bar. it sounded like it came from the entrance area. we didn't see the shooter, didn't see the flashes from a gun. we were kind of in a daze.

we did kind of duck because it was a loud sound. we didn't foe has know what it have been. after that we snuck out the little back did or where we were at to the outside patio area. we were trying to gather what we her, then we heard a couple more gunshots fired. that's when everyone was running, jumping over the back patio fence. my roommates jumped over. i actually went through the pulse employee hallway forthink i could lock myself in the hallway, i heard more shots inside pulse. i ran back out. my roommates helped me get over the eight-foot tall fence. that's when we all ran for it. during my run i heard mr. gunshots, and a fight or flight situation. i kind of hopped behind an suv.

that's when i then crawled underneath and hid there for a bit. after a few minutes, which sche seemed like forever, i creeped out and made sure the coast was clear because the police perimeter was set about 100 yards away to be safe, as a safe zone. whever i was getting ready to do that, i hatched to see someone covered in blood stumbling through the parking lot. i kind of grabbed him and pulled him over to me, and he was still coherent, but you could tell he might have been a little delusional from the loss of blood. he was, like, hey, man, i think i got shot. i checked. i first only noticed two, one in each arm. at that point is when i took off my shirt and told him, hey, i have to stop the bleeding. i was like, i hope you don't mind, it's going to be really tight. i tied the first gunshot wound

with my shirt. i told him i had to do it to his other arm which is where the second wound was. after that, i told him we needed to somehow sneak over to the safe zone where the officers were and had it closed off. he complained of some pain in his back. i noticed he had another gunshot in his back. so i applied pressure to that area. we kind of hobbled through the parking lot between cars. once we got into the safety zone of the perimeter that was set, the officer then got a bystander to give me another shirt for his third gunshot wound, which he then asked me to apply pressure to it. i did find out his name was rodney sumpter. his friends have been contacting me on facebook. i gave him an update that i took him to the hospital. i stopped as much bleeding as possible. once we got into the police car,

they asked me to lay down first and they were going to put him on top of me because they wanted me to hold him as tight as i could to constrict extra blood flow that was combi icoming out. i'm thankful myself i got away safe. a lot of other people i know and care about did as well. just words cannot describe the feeling being covered in blood, trying to save a guy's life that i don't know. i'm fine, i'm just traumatized at that time. the thing i had to say to the guy in the black ack of the pol car, they wanted me to make sure he was conscious on the way to the hospital. i was saying a prayer for him. i said i'll be there waiting for him as long as i can at the hospital. it stinks because i didn't get his fame at time. i did get his last name as

sumpter. i still don't have an update on him. his best friend ashley has contacted him. his friend aaron has contacted me. they're trying to get in touch with his family. family are the only people able to get information on him. i hope god is with everyone. for whatever reason that may be, i don't know if he put me there to help rodney in that situation. i just hope everyone ask okay. and i do know that there was a mass casualty going on. it's something i didn't expect. something like that, even at pulse orlando. >> josh, thankne goodness you h the presence of mind and heart to help rodney in his most horrying timhorr horrifying time. jen ashton, we just learned about what goes on.

>> in trauma situations, we're trained to look for two things, the entrance wound and if we can see an exit wound. sometimes it can give us an idea what the path was inside the body and therefore what organs are damaged. when you hear story about app applyiapply tourniquets to limbs, typically you don't tie off a body part that you don't plan to possibly lose in a life threatening situation that can save someone's life. but the heroic actions of the first responders and just bystanders here. i'm sure we will hear more about that. >> senator bill nelson is joining us on the phone from florida. thank you for joining us. what is the latest you can tell us about what happened there and the links that gunman may have had to outside groups. >> george, the fbi is taking the lead. both senator dianne feinstein,

the chairman of the intelligence committee, as well as i have talked to the assistant director of the counterterroism center. there appears to be a link to islamic radicalism and not will you the fbi, through other intelligence staff that there is some kind of connection to isis. so the facts will emerge. mike feinbach of the fbi asked me to make the plea to anybody who knows anything about the shooter, he's from ft. pierce, florida, 80, 90 miles away to the southeast of orlando, to come forward with information about the shooter. >> so we're looking for more information right now, gathering more information.

what more can you tell us about the response and the community right now. i know you're heading to the scene. >> it's all hands on deck. i'm down near the emergency operations center. of course the largest mass shooting in america, you can imagine everyone is on edge. >> and, senator t se, it seems we have to do with a shooting like this every few weeks or so the scale of this so devastating. 50 dead. 53 injured. the worst mass shooting in american history. possibly the worst terror attack as well. how do we begin to figure out how to prevent more shootings like this from happening? >> well, this is where we have got to come to grips with this. people have to think of themselves as americans not as a

particular sect of america. we have to come together. that's been the strength of this country is that we think of ourselves as hyphenated, but the common denominator is we're one. when you get so split up with all of these different groups thinking different ways, then that's leading to the unblind cause. speaking of -- you know, we just had a killing -- this has happened in two successive days in orlando. we had the killing of a professional singer performing at the plasma nightclub right here in downtown orlando two nights ago. and now this killing of masses and masses of people. at some point peel have got to look deep inside and say where

are we going as a people and as a society? >> senator nelson, thank you very much for joining us this morning. i know you'll be on top of the scene there. we'll come back to you with further developments. i want to go back to brian ross. you heard the senator talk about how his office is getting some separate information from the fbi and possible ties to isis. >> that's right. a very dramatic turn in the case if it turns out to be the actual fact that there are ties to known islamic terrorists and perhaps to isis. that's something we have not heard until this interview with you. >> and what more, from what we've learned so far about this activity, what more would we expect if isis was, indeed, part of this or had some coordination? you would expect to hear from them at some point, wouldn't you? >> generally yes. sometimes it takes several days before they do that. i think what the fbi willing

will be doing is trying to track all of his communications, if they can get his phone or home computer to see if he had contacts with anyone overseas. if this was directed or inspired or if he was a person who read a lot online and hate messages from isis particularly about the gay community. >> richard, there's been difficulties in figuring out the whole dispute with apple and the san bernardino shooter's phone, and what can be recovered from that phone. these kinds of communications is so critical. i think we might have lost richard clark there. i want to bring this back to brian ross. brian, tracking all of these communications over social media, iphones is important to

getting to the bottom of all of this. >> that's right. there are a number of people who the fbi is tracking on a regular basis because they picked up communications with potential people connected to isis overseas. sometimes people under surveillance, sometimes not. sometimes they're not regarded as threats. certainly, as you say, the ability to track any of his communications will be key. we learned in the san bernardino case a day or two into it that they had been in some sort of shrouded confidential communication with people connected to isis. >> the phrase we keep fearing, pierre thomas, when those terrorists go dark. >> exactly. the process has been described to me in this way, that often the fbi will see communications through social media, through the smartphones, which the fbi director calls like a devil on

their shoulder, every day encouraging people to do something. then these people will go dark, as you say, they suddenly disappear off the grid. the fbi is no longer able to follow them unless they get a full-scale investigation locked in on them. imagine investigations in all 50 states over several hundred people, which the fbi thinks may be interested in isis. then trying to figure out which of these do you do a full-scale investigation on? it's staggering. >> and, john cohen, i want to pick up on a comment that richard clark made earlier. eventually you have to think of a counter narrative to these poem who may be attracted to this ideology on social media. i will bring that to pierre thomas. counter this narrative that is coming in all day long, 24 hours a day, and hitting these young

people. >> the fight is multi teared. one thing that law enforcement and intelligence officials and officials at the state department have discussed is ways to communicate through social media in the same way that isis has to inspire people. i had a senior official tell me more than a year ago that the u.s. advertising community, the top people from new york and los angeles and other people who look at marketing needed to be consulted to come up with a counter plan. he said that the people involved with isis were playing at a higher game than the u.s. government was. >> pierre thomas, thank you very much. i want to go back down to orlando and bring back lewis bervano, who was in the nightclub last night and was able to escape. bring us through again what you saw and heard. >> at least in the front bar

it's not that big. probably 40 feet in length. 20 feet wide. there were over 100 people there. the main dance floor was clearing out. people going to the bars, closing out tabs. it seemed like everyone was gravitatie ining towards the ba end, we were just collecting our checks, then that was it as soon as we jet, i threw myself through the hole in the fence. i was around helping out 10, 15 minutes. the paramedics came, from there they took over. that's when the cops said, okay, let's go. time to go now.

we went a few blocks down, heard a controlled explosion, two more explosions, one more gunshot followed by the takedown. the officers next to us said duck, duck, duck. he w we were behind a huge fire truck. at that point we were there for a little bit, behind the fire truck. we waited about 3 minu0 minutes. we walked a few blocks, were greeted by 150 police officers from florida, little by little hostages were coming from. one of our long-term bar fenders, good friend, was hiding in a small closet with about 8, 10 people, in a small closet. they were starting to make their way. from there, opd transported us to a bus, we went downtown to headquarters and we had to make

our statements. people little by little were just popping out in different parts of the bar -- of the fitting room. he said at one point he got behind the door to drop down a barstool on whoever was to walk in, try to do something. at that point, you know, you either run or you try to make something happen to save as many as you can. we had walked in, my best friend and i were talking, we said, wow, for a good night, it's not that packed. not that dead. it's very quiet but very, very lively. great energy. normally there's little altercations. i would say a couple hundred. i've seen that club at max capacity, elbow to elbow you're pushing through to get to the restroom or for drinks. there was at least a couple hundred for sure. 200, 300 i would think spread out throughout the front bar, back patio, main floor.

it is a great layout. they just remodeled it. they made it look wonderful. it's been a while since i've been there. more people filling in as the night was going on, believe it or not. >> thank you very much for that. i want to put up now, we have a photo, we received a photo of the gunman, omar mateen. you can see him there. 29 years old. american citizen, born in the united states in 1986. a resident of part saint ort st florida. ray kelly joins us now. now you'll have all hands on deck finding out everything possible about this young man. >> right. exactly. obvious i will tell phone information, calls that he made,

e-mail communications, all of those things. where he worked. some indication that he worked in the security field. that he may have had actually a license to carry a weapon because of that work. more of this will come out, of course. but certainly government agencies digging into it. but the media is doing it as well. people want to know as much as they can about this individual. what connectivity he has, ties to other individuals. was he meeting with people? was he talking about jihad to anyone else? this is so critical, so important. that's what is ongoing now. that will be going on with great intensity for the next couple of days. >> ray kelly, thank you very much. i want to put up another photo right now, a photo of a police officer's kevlar helmet which police are saying saved that man's life. you can see it there. it took the bullet.

i want to bring brad garrett back in here. we heard from eyewitnesss. we're getting more information about the shooter and learn more about what was happening inside that club from 2:00 to 5:00, and what the police officers had to do when they went in at 5:00 a.m. one thing we're unclear on, at least i've been unclear on from watching the police briefings so far, were all of the victims killed by the shooter or was there some critical damage when the police went in at 5:00. >> which will take a while to sort out, but not a long while because of caliber of weapons. but the problem is, when you do a dynamic entry into a location where conceivably there are still dozens of people, the lighting is probably not the be best. you may or may not know where the shooter may be. how do you hone that down, not wanting to harm anyone but the shooter. is that possible? yes. particularly when you talk about

return of fire which is how it's described that omar returned fire to the officers, so you have this gunfight going on inside the club. to your question, it is certainly possibility that law enforcement may have hurt somebody else. >> as you were saying earlier, there's no way they would have gone in at 5:00 a.m. unless they had determined or they had concluded that if they don't go in, the bloodshed will go higher. >> it will go higher and it's just not going to end. these are not the type of people that you negotiate out of the scene. you either surprise them, arrest them or kill them. that's really the only options you have. they didn't go in there to talk to you about a woeful tale about their life. they went in there because this is a cause. they think they have moved on to a higher level by doing this type of mass killing. so, with that in mine, that's what you do you collect as much intelligence as you can.

when you believe you can make a move, you make it. they obviously did around 5:00 a.m. >> brad garrett, thank you very much. we want to go back to orlando, lauren lyster on the scene. we are expecting to hear from police and other officials again at 1:30. what can you tell us about the scene right now? >> before we go, they just cleared a portion of this street. allowing us to get as close as we've been able to see of this scene. i want to zoom in, if we can, beyond that auto tinting facility is pulse nightclub. you can see the sign. you can see the black building with the black awning. that's where a fun night of latin dancing last evening/overnight turned into terror when that gunman opened fire around 2:00 a.m. you can see the scene is still filled with emergency response vehicles, still a number of police and fire trucks in the area. as we've heard from a number of

people, there's a scene inside that's grotesque, a lot of evidence that needs to be selected. and so many horror stories of witnesses describing the shooting, bodies on the ground, and blood everywhere. many of those people, family and friends still at the hospital, just down at the other side of the street waiting for answers. george? >> lauren, we know this is a gay nightclub in orlando. was it very, very well known as a gay nightclub? well known in the community? >> well, i have a friend who is based in l.a. who texted me to say how scary, i've been to that club. it's one that was known. it's billed as the premiere gay nightclub in its own words. certainly one of the witnesses that we interviewed earlier, he's new to town. he is not experienced in orlando. this is where he went for a night. he said it was latin night. so it did have a certain

clientele that particular night. there were some exciting performances from drag queens, including a famous one that he said was on rupaul's show. so a night with 300 plus people gathered at the club. it doesn't look particularly large. this is a street with just basic small merchants. a dunkin' donuts lies beyond this. just an auto repair ahead of it. a 7-eleven and an einstein brothers bagel. this is not a big downtown area, but a quiet street. it's pretty startling that this is where such a horrific crime went down. >> a night of fun turning into a nightmare, thank you very much. jen ashton, as you pointed out people will be dealing with this trauma throughout the communitytcommunity for a long time. >> no question. not only first responders and what they had to do, not just

the physical trauma but the emotional trauma who will extend to everyone watching the media coverage of this. we're all experiencing a certain degree of psychological trauma. >> thank you very much. we'll wrap up right now. we'll have a special 20/20 tonight at 10:00 on this carnage. to recap, 50 dead. 53 injured in the worst shooting in american history in orlando overnight. the gunman has been shot as well. the gunman killed. they believe, police believe and officials believe he acted alone, but searching now for ties to isis. treating this as a domestic terror incident. his name there, omar mateen. u.s. citizen, 29 now. stay on top of this. get all the latest news at abcnews.com. i'm george stephanopoulos.