Updated

This is a rush transcript from "The Story," February 14, 2018. This copy may not be in its final form and may be updated.

MARTHA MACCALLUM: It certainly is, Bret, thank you very much. And we have some brand-new information tonight about this shooter. He was taken alive into custody, a short time ago. This shooter, unlike most of the others, did not to die in a hail of bullets or take his own life, after taking the lives of 17 innocent young people today in the State of Florida. This young man will have to talk. He will have to face justice. And that is something that you rarely see in the deadliest shootings that we have seen in our schools in America since the columbine. He reportedly pulled the fire alarm into draw everybody out. Remember, they had a drill, a safety drill just that morning. Witnesses, of course, thought this is just another drill, they describe now what they saw.

(BEGIN VIDEO CLIP)

UNIDENTIFIED FEMALE: We heard gunshots. We heard him going up and down the hallway, and he shot in my door -- shot at my door and we --

UNIDENTIFIED FEMALE: In the hallway, we saw a big pile of blood like kind of smear as if they were dragged away. And I saw two girls, probably, dead in the hallway, and coming down the stairs, there's more blood, and outside of the building there was another dying. I think there was a teacher who was, I'm pretty sure, was dead.

UNIDENTIFIED FEMALE: There was just a lot of blood everywhere and there are bodies. I remember my friend crying behind me. I kept telling her that it was going to be OK, and we're going to get out. And luckily, we did get out.

(END VIDEO CLIP)

MACCALLUM: Unbelievable, right? I mean, these poor kids, they have not even begun to process what happened to them today in their school. And as this so often the case now, the first awful sense for everyone involved that something was wrong came by text message. A student inside sending this chilling message to a family member of one of our producers: 'Joe, there is gunshot here at my school. I'm super scared. I love you. I'm really scared. Don't call me, Joe. I'm really scared. Call the police, if you can. Please, I cannot talk. Joe, I have to be silent.' So, we will hear from that young man, a sophomore in high school in just a few moments. And the adults, of course, were in shock.

(END VIDEO CLIP)

UNIDENTIFIED MALE: It's just catastrophic. There really are no words.

UNIDENTIFIED MALE: It's a horrific situation. It's just a horrible day for us.

(END VIDEO CLIP)

MACCALLUM: Phil Keating, live on the ground as he has been throughout the afternoon with the latest for us tonight. Good evening, Phil.

PHIL KEATING, FOX NEWS CORRESPONDENT: Good evening, Martha. A very stone- faced and grim Broward County Sheriff Scott Israel said 17 lives were lost today in a very somber, somber and short press update here about half an hour ago. 12 of those bodies remain in the school; two of the bodies were shot and killed outside of the school; another person shot and killed down the road on pine island drive, and two died while being treated for their wounds inside the hospital.

A total of 15 people were also wounded, and taken to the hospital. The extent of the injuries, unclear. So, we don't know whether or 30 or 32 people were actually shot by the alleged gunman or some of the injuries came during the massive panic and evacuation. But that gunman, a 19-year- old student expelled from this same high school in the past, according to the sheriff, identified as Nikolas Cruz. Somebody described by other students as having a fascination with guns and bombs, and some student actually said that it was the kind of guy that I wanted to steer clear from.

That was the person identified by witnesses as wearing a black hat and burgundy shirt, black pants and then, within about an hour and 15 minutes, a person wearing that exact outfit, as captured by our Miami Fox WSBN helicopter shots, that is the person that was handcuffed and led away in a squad car and treated at a nearby hospital. He has been released from that hospital and is now being processed. The sheriff would not tell me whether he had any indication as to what the motive may have been.

He is convinced that they do have the lone killer in custody. They're not looking for anybody else. The school, which is about a quarter-mile over my right shoulder, camera left, has been cleared classroom by classroom by the squad teams, but those 12 fatalities still in the school and the sheriff would not specify whether they are all students, whether they are a mixture of students and teachers, nor their ages. But the school itself has 3000 people, roughly, all four grades. Other students that I spoke to who were 19, 20 years old who live in the area this afternoon said that your average everyday American high school, nothing really to say beyond that.

But unfortunately, today, on Valentine's Day the worst school shooting in this county's history. Speaking of Valentine's Day, one of the students inside the school aside from hearing that second alarm of the day being pulled said that he heard a few pop, pop, pops. He thought that those were probably Valentine's Day balloons being popped by rambunctious students down the hall and other classrooms because a lot of the classrooms have parties today. But, of course, that student was unfortunately, deadly wrong. Those were not balloons being popped, but gunshots coming from a man who that the law enforcement here says had multiple clips of ammunition on him and included a one semi-auto rifle -- AR-15 semi-assault rifle. Martha.

MACCALLUM: Phil, thank you very much. Joining me now on the phone, Christine Hunschofsky, she's the Mayor of Parkland, Florida. Mayor, I hope that you can hear me, do we have you there?

CHRISTINE HUNSCHOFSKY, MAYOR OF PARKLAND, FLORIDA: Yes.

MACCALLUM: Christine, first of all, our condolences. I mean, I'm sure that when you woke up this morning, this was the farthest thing from your mind on a Valentine's Day; a sunny day in Parkland, Florida. What has today been like for you and what can you tell us, if anything, about this suspect and about what happened?

HUNSCHOFSKY: This has come as a shock to everybody in our community. For those of you who aren't familiar with our community, we're in the northwest corner of Broward County, we're a small city, very family-oriented, very community oriented, close-knit city. I could never imagine that something like this would have happened here. I found out this afternoon; we got a call that there was the EMS and police responding to an active shooter situation at the school.

I immediately came over in the beginning, you know, parents were not getting any information. Very thankful for technology today with texts, so that many of them heard from their children inside that they were OK. And then, as time progressed and the police were inside, they were going throughout the building step-by-step and as they cleared certain areas they were letting students out. And as you can imagine, parents being able to hug their children after what they'd been through, they were, it was a very emotional scene.

MACCALLUM: Absolutely, and, you know, your heart breaks obviously for the 17 families who are dealing with the worst news of all on this day.

HUNSCHOFSKY: Absolutely.

MACCALLUM: What are you hearing in your town about this suspect?

HUNSCHOFSKY: I spoke to a few students as they came out and some parents. The parents seem to have recognized in the name, they were given the name by their children and they seem to recognize the student’s name. I didn't really hear much more than that, but his name was known to some of the parents.

MACCALLUM: He was 19-years-old and had been removed for disciplinary action. That's what we know so far.

HUNSCHOFSKY: Yes, that's what we found out.

MACCALLUM: And we're going to learn quite a bit more about him as all of these progresses, which is awful, awful. Do you know whether or not to there were any teachers, because some of the students talked about seeing an adult down?

HUNSCHOFSKY: I have heard the same thing, but I have not received any first-hand information regarding that. But I heard the same from the students.

MACCALLUM: OK. You know, as he looks forward, and obviously you start to look at the statistics, and, you know, none of these human beings feel like statistics to you, they're your neighbors, and your families and we were going to be dealing with all of this for a long, long time. But what goes through your mind in terms of what might prevent something like this? Or if anything what can be done differently?

HUNSCHOFSKY: And that's the tough question. I think if there were anything to answer, someone would've come up with it so far. I would just hope that at some point in our society, we have the focus and the determination to look at these cases and roll up our sleeves and try and work towards what those solutions could be. Because I don't think that there is one solution, and I do not think that there's an easily solution.

MACCALLUM: No, there certainly isn't. Christine Hunschofsky, the Mayor of Parkland, Florida, thank you and our thoughts are with all of you and everybody who is dealing with this tonight. Thank you for taking a moment with us. We appreciate it.

HUNSCHOFSKY: Thank you. We appreciate that. It's a tragic night for all of us.

MACCALLUM: It certainly is. Thank you very much, mayor. So, joining me now on the phone from Coral Springs, Florida is James Harrison, he's a sophomore student who was on the same floor when the gunman opened fired and the text message that we showed you earlier that James was reaching out to his stepfather. James, how are you doing and what was going through your mind when you were reaching out to Joe today?

JAMES HARRISON, PARKLAND SHOOTING SURVIVOR: Well, I just couldn't believe it, because there were so many shots that I heard and I was so scared and I was so anxious; I did not know -- and I saw everybody else in the class, they were all texting their family members. So, I just ended up picking up my phone, you know, doing the exact same thing trying to contact. I contacted my stepfather, my mother, and both of my brothers and trying to get them to call the police. When I was in class, we had not known that it was not a drill, because the school left the door open -- and so, you know, we never ended up having the shooting drill. And so, everyone figured, oh, this is probably going to be a drill to test to see, you know, the teachers how to open the door and response. And we ended up finding out by a woman on CBS News, and we saw online that there was a shooting at my school, and so we all had confirmation that there was a shooting.

MACCALLUM: You know, James, you've done these drills before at school as kids all across America have done, and I'm sure you never, ever thought that it would actually happen at your school. Do you think it's even sunk in yet what happened today?

HARRISON: No, honestly, I believe that I still don't understand exactly what happened. You know, I just -- I still feel a little like, I'm still shaking a little bit, my heart is still pounding. I still have a bunch of adrenaline. Right outside my door right outside the class door, you know, I heard the shells of the bullets from the gun. You know, right then and there, I was like, oh, my God, what is happening? This is horrible. And, you know, I just, I couldn't -- I just told myself that -- and we're all just sticking together, and we were so upset. We made sure that we waited it out and figure a way out no matter what.

MACCALLUM: I'm so glad you did and I'm sure your family has been through so much today. And you know, we're grateful to talk to you. I just want to ask you: do you have any awareness of who this shooter was. Did you know anything about him, Nikolas Cruz?

HARRISON: I actually never knew this person. I came to the school last year. I never had seen him. My friends claim that he saw him last year; he's a junior guy. And he saw him last year at a lounge, and he told me that he was very, like, quiet person and kept to himself. He was a very, you know -- he (INAUDIBLE).

MACCALLUM: James, thank you very much for talking with us tonight. It's good to have you with us. And I am so glad that you're OK. And it's just a difficult, difficult day. And thank you for sharing what happened and for sharing your text message which, I'm sure, was just the way that so many people got news today. So, James, do take care, all right?

HARRISON: You too, have a great day.

MACCALLUM: Thank you. Thank you very much. So, as Phil Keating reported moments ago, the buildings have been cleared at the school, four t0 five different SWAT teams went room by room. Lt. Col. Tony Shaffer, CIA-Trained Intelligence Operative is here on another story with us tonight. But obviously, Tony, this is what all of America is watching.

TONY SHAFFER, INTEL OPERATIVE, CIA: Absolutely.

MACCALLUM: And you think about the protocols that are put in place, because all of these schools, as James was just saying, they did a drill this morning. I don't whether this shooter knew that they did a drill this morning --

SHAFFER: I think he did.

MACCALLUM: He may have, and thought this might be a good time to do this. But he pulled the fire alarm. So, of course, everyone is going to run out, right?

SHAFFER: Absolutely, this is a thing, and my condolences go out to the family and students of those they lost. I have an 11-year-old, a 23-year-old son who is a fireman, who would rush and in a situation like this. So, this is very personal. We have to understand, Martha, that this individual had what we call 'insider information'. He knew the process; he's student a former student. So, he planned this. I think we're going to come to find that he had meticulously kind of laid out this plan in advance. He was apparently known to the student body, and I think what we have to be concerned about, and, you know, I'm just talking to a teacher who had some experience with this right before I'm coming on, this is a culture where we have individuals who are kind of on the radar; they are of concern but where do they cross the line? Where do you measure personal protection rights? And I would say to say this individual may have actually purchased that weapon legally in Virginia. You can be 18 and purchase a firearm, so this kid --

MACCALLUM: He's in Florida, though.

SHAFFER: I don't know about Florida. But I'm saying that that could be -- this is something in one of those situations where as the mayor was saying, there's not one single answer and the ones that we have to come up with are going to be difficult or we have to seek them.

MACCALLUM: You know, and as I said in the intro of the top five deadliest school shootings, this is the only one where we have a suspect in custody. So, he is going to answer questions. They're going to learn what was going on in this young man's mind, we hope. You know, in terms of how we stop these sorts of things, you know, you think about the fact that we've done stories where, you know, a little kid can draw a picture of a gun and they pull them up. Now, this kid was pulled out of the school.

SHAFFER: Right, he was on the radar.

MACCALLUM: So, I mean, you could argue that the school did the right thing, right? They removed him from the school, he was told that he could not return to the grounds, at least according to one report that I read with a backpack. What more can the school do than that.

SHAFFER: That's a good question. So, I work with Sheriff David Decatur in Stafford County, as Homeland Security Adviser, we studied this issue regarding not only schools, but churches, malls, and that sort of thing. Because, Martha, what happens when someone becomes a threat, they're on the radar, how do you then do that? It's all about local policing. Somebody had to know, Martha that this kid was going to potentially do something. And I would ask you, where were his parents? I mean, you know, I'm very close to my kids. I try to maintain contact with them. But something broke down here at the community level. So, I think we have to look at partially how we look at threats. And one of the things all schools should look at is that there are maybe mentally disturbed children, like this kid, out there who may want to do copycats. So, every school should be right now rechecking all of the vulnerabilities. They've to be very cautious this time.

MACCALLUM: He's on chat rooms --

SHAFFER: Precisely.

MACCALLUM: -- about guns and violence. One of the early reports said that he was looking at some, you know, even some overseas videos of action in, you know, other countries Syria and the like. I don't think there's any indication that he had any connection to that. We don't know yet. We'll find out. But when you know all of these things, right? What can you do?

SHAFFER: Well, no, but see something, say something. I mean, again, there had to be some level of detection going on. And so far, you know, there's multiple reports saying that the kids knew that there was something wrong with him. As you pointed out, he was banned from coming on campus and having a backpack. He was on the radar. But that becomes the point of departure. Once we learn everything, how do they get the gun? Was he on drugs? Because the columbine kids were actually on some sort of psychotropic drugs. And the other thing to remember, one of the congressmen that was on earlier talked about the fact that the kids during his day would have guns in their cars and go to school.

When I was 13, I hate to admit this, I was allowed to go to upstate New York and run around on a farm with a 22 rifle, at 13-years-old. I never was contemplated about using a gun for violence. So, this where something has happened in the culture. And this, you know, we have to understand that there's something going on. Mara Liasson said with Bret earlier that there have been multiple shootings this year not this level. And kids broke into a gun store -- a high school kid broke into a gun store, in the end, to get guns. So, clearly --

MACCALLUM: You know, you have to ask if what the impact is of social media.

SHAFFER: Right.

MACCALLUM: Of you know, the pressures that kids feel. You know, this kid has been kicked out of school, I don't know if he is looking at social media. He's seeing other people having fun doing things together. I don't know. Who knows? We'll find out. But that pressure potentially is weighing in here in some way, shape, or form.

SHAFFER: Oh, absolutely. I think you now have a culture which accepts violence as part of its speech. And this is what we see, I think, across the board; people are more willing to accept this. And this is diminution of culture. It's not simply about guns, it is about the fact that this kid was probably so ramped up, he may have used a car to mow these kids down. You can use a car for a weapon. So --

MACCALLUM: But as Mar also pointed, you know, that's often the argument against gun control when we have these conversations, but nine times, it's a gun.

SHAFFER: It is a gun, but we have to figure out how it got into his hands. Because this is another issue -- there's no reason for someone like me who's been in combat, who actually understands how to use a gun to have it, but clearly, he should not have had it. Somewhere, there's a solution. And I'm not sure where that solution is yet.

MACCALLUM: I mean, are we going to put a fence around every school and have a checkpoint to get into the -- onto the property?

SHAFFER: Some schools already do. I mean, my son's school, you have to go to the front door and you have to be buzzed in.

MACCALLUM: But in this case, he was smart, he pulled the fire alarm, and everybody runs out. So, he knows how it works, and he's getting past the system.

SHAFFER: Right, and so the schools need to relook this vulnerability. We have to always stay ahead of them. Unfortunately, Martha, there's just no way -- and again, I feel so horrible about this, because it touches close to home, but we need to find the answers, and there's not simple one. There's going to be a number of things that we have to look at after this.

MACCALLUM: So, he's in Florida.

SHAFFER: Right.

MACCALLUM: He's 19-years-old. They have a death penalty in Florida. We're going to see a trial process play out here the likes of which we have never seen in a school shooting.

SHAFFER: Right. Well, that's the thing. I mean, we need to do a very thorough examination of soup to nuts of everything that happened, how did this kid get to this point, where did the weapon come from? What was the school doing? And just lay it all out, because there's going to be clues about what to prevent the next one. And I don't -- again, it's not going to be simple. I don't think we're going like some of the answers we see, but I think we have to take a hard look. And to your point, we have someone who was captured and he can tell you a lot about what motivated and how we -- and that's going to be important.

MACCALLUM: Tony, thank you very much.

SHAFFER: Thank you.

MACCALLUM: We're going to stay on this, obviously. So, as you've heard, we've got new details that are emerging tonight about the suspected shooter behind today's deadly shooting at Marjory Stoneman Douglas High School in Parkland, Florida. His name is Nikolas Cruz, a 19-year-old former student. He was kicked out of the school. He was accused of opening fire within AR-15 rifle and killing 17 innocent children and perhaps an adult. We're waiting for the final breakdown and the numbers on this horrific shooting today. So, joining me now, Trace Gallagher, who has been looking into this, he has the latest on the shooter for us tonight. Hi, Trace.

TRACE GALLAGHER, FOX NEWS CHANNEL HOST: Hi, Martha. Just minutes ago, the sheriff confirmed that along with the AR-15 semi-automatic, you mentioned, Nikolas Cruz was carrying countless magazines intimating the attack could have gone on much longer. It's unclear where he obtained the rifle, but former classmates of Cruz say he was obsessed with guns and would show them pictures of guns on his cellphone. They say Cruz told them that shooting weapons gave him an accelerating feeling. At his social media account certainly backed that up. On Instagram, Nikolas Cruz followed several gun groups. He even followed resistance groups like Syrian Resistance Fighters, and fighters from Iraq. Tonight, the Broward County sheriff made it very clear that Nikolas Cruz's social media footprint was very concerning. Listen.

(BEGIN VIDEO CLIP)

SCOTT ISRAEL, BROWARD COUNTY SHERIFF: If you see something, say something. If anybody has any indicator that someone's going through a behavioral change or on his social media that there were disturbing photos, perhaps bombs, or firearms, or just, you know, videos or pictures that are just not right, please make sure law enforcement knows about it.

(END VIDEO CLIP)

GALLAGHER: In fact, it appears the 19-year-old suspect recently took part in a YouTube chat room dealing with bombs. When police learned about the online forum, they immediately warned police SWAT teams at the high school to be on the lookout for any signs of explosive devices. So far, there is no indication that they found any. Nikolas Cruz was also reportedly a former member of the U.S. Army Junior Reserve Officers Training Program. The sheriff says, he was expelled from school for disciplinary reasons, though, he did not elaborate. But a student tells our Miami Fox affiliate that Cruz was a loner and has had problems for years, saying he left school a few months ago after his mom died and moved to North Florida.

A teacher at Stoneman Douglas High School told the Miami Herald that last year Cruz threatened some fellow students and was told not to come back on campus with a backpack. Though the school superintendent says he isn't aware of any threats or warnings involving the suspect. And we should note the campus does have a full-time police presence. There are numerous reports, as you've talked about, Martha, saying that Cruz open fire, pulled the alarm as a way to draw more students into the hallway. Tonight, the sheriff says he knows nothing about the fire alarm. And finally, the suspect's injury, we're told, was not significant at all. Martha.

MACCALLUM: Trace, thank you very much. So, as we've discussed, this horrifying case offers authorities the rare opportunity to question this gunman. Since 1999, and every single case of deadliest school shooters took their own lives. John Iannarelli, retired FBI Special Agent joins us now. John, good to have you with us tonight. We know that the FBI was on the scene early on in this case. What's their first motive of operations here?

JOHN IANNARELLI, RETIRED FBI SPECIAL AGENT: Well, the FBI is there to support the Broward County Sheriff's Department. They are the primary agency. The FBI is going to give resources by helping to collect the evidence, conduct interviews. But most importantly, they're going to look at everything this person has done on his computer, anything that he has written, social media. That hopefully will put together a timeline and maybe give us a motive.

MACCALLUM: You know, when you look at this, we have obviously such a huge problem with this. We've got -- this is the second fatal shooting in 2018; it's the fourth in the last ten months. As law enforcement, what kind of recommendations are there to try to change this culture that has gotten us here in this country?

IANNARELLI: There's a lot of talk about things like we should have more gun control, we should teach people what to do with the active shooters. All of that, there's places for, but the reality, there are certain things you cannot prevent 100 percent. But students at the school, teachers and certainly family, need to be aware if there's a problem in the family, if someone acting strange or expressing things like this person was, posting on social media. That's the time for mental health intervention. It's something that we have to take more seriously. We've seen it in other cases and we've seen it here today.

MACCALLUM: But in terms of the rules for law enforcement, for the FBI, for local police officers, let's say someone came to the school in the school passes along the message. Look, as we've heard from some of the students today, he showed me guns on his phone, that he owns or that he had in his possession. He has been participating in gun groups on YouTube. He's been watching Syrian and Iraq resistance fighters on YouTube, what would you then be able to do based on that information?

IANNARELLI: Well, currently, not a lot. And if Congress wants to get together and argue about something, here's something for them to discuss. Certainly, we want to protect first amendment rights in this country, but at the same time, we want to protect our citizens. We have to make sure that there are avenues for law enforcement to get involved. He's an 18- year-old adult, there is nothing law enforcement can do to arrest somebody like that. But if he was a minor, we'd be able to take somebody into custody at least for an evaluation. We have to be able to give law enforcement the tools to make sure that they can keep the public safe.

MACCALLUM: So, because he's over 18, you can't go talk to him?

IANNARELLI: As an adult, law enforcement can talk to them, but can they take any action? Just because somebody espousing views of guns or anything else, that's freedom of speech. Until they make a specific threat that they want to go to a school and hurt somebody, there's no legal action that you can take. But if a minor does something like that, the laws are less stringent. We have to be able to at least refer people for a psychiatric evaluation when the circumstances put together warrant such.

MACCALLUM: Yes. I mean, you look at what child services is able to do. And you feel like when there's this kind of activity going on, people are being told if you see something, say something, and they want to feel like if they say something there's going to be some sort of action taken that might send this person in a slightly different path that prevents something like what we saw today. John, thank you very much. Good to have you with us today.

IANNARELLI: Thank you.

MACCALLUM: Joining me now with more, Bernard Kerik, Former New York City Police Commissioner. Bernie, good to see you tonight.

BERNARD KERIK, FORMER NEW YORK CITY POLICE COMMISSIONER: Thank you.

MACCALLUM: What do you think?

KERIK: I think it's bad, it's more than bad. For me, what's concerning is that they had all of these warning signs. There have been kids interviewed already that talked about he had issues. Everybody seemed to know that he had issues including the school where he was expelled from. He has all of this online chatter and these postings of guns and weapons and knives and these chat rooms. And this is -- you know, I agree with your -- the prior speaker, this is something that Congress has to look at. When you have somebody that has mental instability and they're floating around with all of these weapons. Well, then it's time -- the police and law enforcement authorities have to have the right to go in, and at least take the weapons, at least interview them -- some sort of intervention. You know, if you had this going on in New York City and they were licensed to carry or licensed to possess and they had all of this chatter and all the stuff online, I can promise you that to the New York City Police Department would be there, you know, within an hour or two taking their guns.

MACCALLUM: You know, you think about the fact that if a police officer walks by your house and they see something inside your house happening, right, they can get a warrant, they can come in. So, we need to get to a place where there's the same sort of situation in terms of what you're doing online that people in the public are able to see. You know, at some point it's like, you're open door, your house is open and you're seeing what's going on inside, you have to have a way -- if you see something, you say something has to get you somewhere.

KERIK: But you know what, Martha, this has a lot to do with training, and training the kids at school. I have two daughters, they're in high school -- a senior and a sophomore. If they're sitting around at home talking about some kid that's acting like a maniac at school and posting these photos and all of this nonsense, talking all of this nonsense online, as a parent, not the kid's parent, as somebody else's parent, I'm going to call the school. I'm going to call the authorities and say, look, this is something that should be looked at. A lot of parents are afraid to do that. A lot of kids are afraid to do that. I think this has to be these are programs that the schools have to get involved in to teach the kids how important this is. Because in every one of these circumstances, every one of these school shootings, we always hear after the fact.

MACCALLUM: Within hours today, people, you know, oh, yes, I know who this guy is, he's trouble.

KERIK: Exactly. Exactly.

MACCALLUM: So, you know, in terms of -- so, it feels like what you're saying as we've done sort of part of the work, we've hardened the schools to some extent, right? You do have to buzz. I remember when my kids were little, you could walk right in the front door, and now, you've got a buzzer and they have to see you on the camera and then they let you in. So, those kinds of things have happened. Some schools have armed guards, some schools are very against that. Should all schools have armed guards?

KERIK: Personally, I think they should. You know, we're doing active shooter programs. We're doing, you know, mock drills and tabletop exercises, all these other stuff.

MACCALLUM: Yeah.

KERIK: But you know what, it's like Tony Shaffer said earlier, you're not going to prevent every incident. You're just not. You can be right 99percent of the time, but that one time they can slip through the cracks. And in this case, this guy knew where he was going, he knew what he was doing and he knew the school. And I think -- I think they're going to find out his primary target was somebody on the third floor. Why would he go to the third floor? You know what I mean? There were freshmen up there. I personally think just listening to what I've heard, he's looking for a teacher, may be. And in the process he did what he did.

MACCALLUM: It sounds like he shot his way into the building because of the two people that he killed outside he killed first.

KERIK: Right, on the way in.

MACCALLUM: He didn't want them to tip anyone off, so he shot them and then went up through the hallway and, perhaps, you're right, he was looking for some teacher who wronged him or something along those lines. In terms of his weapons, he had an AR-15, that raises the question, you know, these are rifles that used to be illegal and now they're not, should that change?

KERIK: That's up to Congress. And believe me, there'll be plenty of people debating that over the next few days, next week, two weeks. I think at the end of the day, one, we want to find out if it was legally purchased, if he legally purchased or somebody bought it for him. We've seen a lot of that lately. The gun that was purchased for one of the guns that killed one of the cops was purchased by somebody else lately. So this is stuff to look at. But I think for right now, schools around the country have to learn from this lesson, and they've got to create a flagging mechanism of some sort to look at these kids. You expel a kid from school for these types of threats and activity, well, then, somebody got to be looking at them.

MACCALLUM: Bernard Kerik, thank you very much.

KERIK: Thank you.

MACCALLUM: It's good to see you tonight. So a short time ago, my next guest said that our worst fears are being realized. Local authorities are currently taking the lead in this investigation with help from the federal investigators and the FBI, as we said. Florida senator, Bill Nelson, joins me now. Senator, thank you very much. We know that you and everybody in Florida, and really across the nation is just wheeling tonight. And we still don't know the details about who has been lost and those families are just processing that, your thoughts? And do you have any new information about what happened today?

BILL NELSON, U.S. SENATOR: Some new information, the gunman was wearing a gas mask, he had smoke grenades. He hit the fire alarm so that all of the kids would start coming out of the classrooms, and then there he had a massive people in a closed space. So you can see how premeditated it was. And then with an AR-15, high caliber, rapid fire weapon, tragically, there are 17 sets of parents that are just grieving very, very terribly right now.

MACCALLUM: So he had a gas mask on and he threw smoke bombs into the hallway? Is that what you're hearing?

NELSON: I cannot confirm that he actually threw them, but that is the implication with the information that I got from the FBI.

MACCALLUM: So in terms of what's going to happen now, do you have any information on whether they're already questioning him? I'm sure. Do we know whether or not he's being forthcoming, any information on that?

NELSON: Well, they took him into custody, and I certainly assume that they would be talking to him. He's of legal age. He's over 18. And certainly if I were in that situation I'd be interrogating him.

MACCALLUM: A 19-year-old who commits mass murderer in the state of Florida, what is he facing?

NELSON: Well, you'll have to ask criminal attorneys, but he's of age, so he ought to be looking at the worst penalty, which is the death penalty.

MACCALLUM: Yeah, there's death penalty in the state of Florida. And as you point out, he's an adult and it's highly possible that he could face that. You know, I would imagine that there are some conditions that attorneys would try to convince that he is not mentally stable, something along those lines. Maybe the defense that we see is too early to say. In terms of what's happening right now in Florida, and outreach, and possible discussion of change in terms of how we handle these situations, or prevent them, any thoughts on that tonight, senator?

NELSON: Well, mental health, clearly, is one. And another is how many times is this going to go on? Until the American people say, enough is enough. Just in Florida a year ago, the mass shooting at the Fort Lauderdale Airport in the same county where this shooting took place. Two years ago, 49 people gunned down in the Pulse Nightclub in Orlando. That's just in our state. And at some point, people are going to say, enough is enough. Now, you're talking to somebody who supports the second amendment. I grew up on a ranch. I've always had guns.

I am a hunter. I haunt today with my son. But an AR-15 is not for hunting. That's for killing. And so, we've got to go through these things. But it's very hard to pass this. Let me give you an example, as common sense a proposal as Senator Feinstein's bill that we tried a few years ago, that if you're on the terrorist watch list, the terrorist watch list, you couldn't buy a gun. We couldn't get that past. So you see the political difficulty.

MACCALLUM: I do. I do. And America does. And I think you're right. I think we've got to talk about this. And it's cold comfort to those families tonight, but it's a conversation that needs to be on the table. Senator, thank you very much. It's very good to have you with us. And again, our thoughts and prayers are with everybody in your state as they deal with this tragedy tonight. Thank you very much, senator.

NELSON: Thank you.

MACCALLUM: So let's go back to Phil Keating who has the latest update for us from the ground in Florida, tonight. Phil?

PHIL KEATING, FOX NEWS CORRESPONDENT: Well, Martha, as you may have heard, Senator Nelson there saying, the suspect was wearing a gas mask. Has smoke bomb on him. In addition to what the sheriff, Scott Israel of Broward County confirm to us in the 6:00 hour, was equipped with multiple clips of ammunition on him when arrested, also had that AR-15.

And he would not answer my direct question of whether he believed that he just woke up this morning hell-bent on causing massive destruction, but certainly, that is exactly what this alleged gunman did. Accused of killing 17 people inside the high school, that is a quarter mile down the road behind me here. You can't get close to it, but 12 of those fatalities remain inside the school.

It remains an active crime scene. SWAT teams have in fact cleared out all of the classrooms at this time. All of the students and teachers are now far off campus at this point. And parents and their students, their sons and their daughters, after a very panicked and terrifying afternoon have been reunited. But, of course, for 17 families, this is beyond belief that one of the worst nights they can ever imagine. Martha.

MACCALLUM: Enormous carnage and enormous loss. Phil, thank you. So let's go back to Lieutenant Colonel Tony Shaffer who joins us once again, CIA trained intel operative. Tony, just seeing this coming over from one of our producers, a tweet from the Broward sheriff saying that the FBI has set up a website where you can upload images and video of the shooting at the high school today, and this is the world that we live in. But, obviously, they want to see if there might be any clues in anything that came in.

TONY SHAFFER, CIA TRAIN INTELLIGENCE OPERATIVE: Sheriff and I were just texting on this issue. One of the things you have to do in a situation like this is to collect everything, because to your point, you have someone who's alive. And now, it's the ability to kind of re-social engineer how this all happen. We have to understand, Martha, today's youth are impacted on drugs, on gangs, MS-13, we've seen an uptick in individuals, these children who have now recognized that, hey, violence is OK.

So this is where the schools have to be very much aware and on guard. At the same time, we have to really examine community policing. I just heard my friend, Bernie Kerik, you know, he was talking about the fact that this kid was probably there to do something.

He was after a target. There may be some symbology of today being Valentine's Day related to why he picked today. But he clearly had what we consider asymmetric concepts. He understood you hit that alarm, you hit the fire alarm, people react a certain way, and he was there to ambush them. So, these are all clues to his psychology, and why he did it. And again, I agree with Bernie, I think we're going to find that he was there for some purpose. There's some reason that triggered today.

MACCALLUM: Yeah. I mean, I think of the shooter in Colorado, in the movie theater, obviously, very mentally disturbed.

SHAFFER: Very.

MACCALLUM: There were some clues in that case. There appear to be some clues in this case as well in terms of his mental state. But there's predetermination as well as you point out. I mean, he had accumulated all of these magazines. Now this video that we have right now, you guys coming in, do we know? That may be the shooter as he was -- that was from earlier, but he was brought into -- they took him to the hospital, first of all, if you're just tuning in. And then they quickly determined that there was nothing physically wrong with him and they moved him from the hospital as you see in the hospital gown, into the facility of the police station there. In terms of determination, and premeditation and mental health.

SHAFFER: Well, look, one of the common factors we've seen in a number of these shootings, includes Sandy Hook and others, there was some level of drug involved, legal drug -- I mean, some of these kids have been under some sort of influence. So I'll be very curious, Martha, one component of this, was he under some sort of doctor's care which allowed him for, or was using some sort of psychotropic drug. These things, I think, have resulted, again, our children being socialized in a way that they accept through this orientation and affiliation of violence that is common.

And not only is it violence, but is the tipping point for concepts of violence. And some people will talk big. I mean, you'll see kids today, like during our age, you know, oh, my dad is bigger than your dad, but it's changed now. Now, you know, I'm going to threaten you and it may create social drama. A lot of kids are driven off of this adrenaline of the drama. You know, the high school stuff, but it's different now. It's different than when we did it, because there are drugs involved, there's more gangs than ever. And again, there's -- somehow these kids are getting a hold of weapons. And this kid may have gotten one legally because he was over 18.

MACCALLUM: Yeah. I mean, time and time again, we see the same sort of awful cocktail of, you know, kids who spends too much time online --

SHAFFER: Right.

MACCALLUM: -- has a mental condition and may be on medication, and has access to the weapon to carry out this kind of thing. All three of those are in some ways unique --

SHAFFER: Yes, ma'am.

MACCALLUM: -- to our environment right now.

SHAFFER: Right. And this is where, you know, we've got to -- I hate to be redundant, but we've got to study this. And to your point, I'm glad you're emphasizing this more than anyone else on the air that you have someone who is still alive. They were not killed. They're apparently in pristine condition, all things considered. And we need to examine that. He needs to be prosecuted to the full extent of the Law because I think -- while he may be crazy, he knew what he was doing. This was a very rational act of violence, may not be terror, but clearly it was meant to terrorize those he was targeting.

MACCALLUM: Yeah. I mean, we're talking about the criminal and I'm watching this video, once again, where you see children running for their lives.

SHAFFER: Right.

MACCALLUM: And really, the focus should be on these 17 families, we don't know who they are right now. So all we can say is that our thoughts are with them. They're having the worst day of their lives.

SHAFFER: Right.

MACCALLUM: And they will probably have years to come of recovering from what happened today. And we will continue to dig in on this very difficult day in the state of Florida. We will take a quick break and we'll be back with more breaking news on the suspect, and on the 17 families who tonight are suffering the worst imaginable loss. We will be right back with more of The Story.

(BEGIN VIDEO CLIP)

UNINDENTIFIED MALE: And we already begin to -- began to dissect his websites and things that social media that he was on. And some of the things come to mind are very, very disturbing.

(END VIDEO CLIP)

(COMMERCIAL BREAK)

(BEGIN VIDEO CLIP)

UNINDENTIFIED FEMALE: I was praying to God thinking that he could save us all -- we can make it alive. I called my parents -- it was just all crazy. All you could think about was, oh, my God, my family, my friends, everything. Like you never think it would happen to you, but it does.

(END VIDEO CLIP)

MACCALLUM: It did, today in Florida. Awful to hear these young kids who are just never going to be as innocent or feel as safe as they did when they walked into school this morning. Trace Gallagher has been following this all afternoon as this news has continued to break. And he joins me once again now. Trace, good evening.

TRACE GALLAGHER, FOX NEWS CORRESPONDENT: Yeah, Martha, we're kind of just digging into his social media background. And as the sheriff said earlier, there really are some disturbing things as you dig deeper there. His Instagram there are pictures of him that shows him brandishing weapons and knives, and there are some texts and some captions that we really can't even repeat on television.

We can tell you that there was one picture of a target riddled with bullet holes and the captions there reads, group therapy that you really should try it. Friends of his telling our Fox affiliate in Miami that he had guns at home, several guns, and that when they would visit him he would talk about using those guns. We talked earlier about how there was this threat warning at the high school. One teacher telling the Miami Herald that last year, apparently, he made some threats to some fellow students and that he was kicked out of school. And then a warning was sent out to all of the teachers, and the faculty saying that if this student comes back on campus with a backpack you need to notify security right away, because he has been identified as a security threat.

We should also point out that what we mentioned earlier that he, actually, on his Instagram page followed various resistance groups. We're talking about Syrian fighters and fighters from Iraq, and it delves deeper into that. And some of them are really kind of in the weeds and we're just not quite clear if those accounts have been verified. So we're not quite going to go there yet. But the sheriff and the FBI, now as they scour his social media footprint, they will be, of course, looking for any leads that will give them any indication as to what caused this or any motivation as to why he did what he did. There were some girls, some young classmates that said, you know, he kind of creeped them out.

That's a quote from them saying, not because they thought he was creepy, but more because he dressed creepy. That he was actually trying to outwardly get people's attention that he was, you know, different from everybody else. In another quote here, preppie in a creepy sort of way. So we're finding a lot more out about this. And it really is fascinating of all of these school shootings we have covered over the years, Martha, very seldom do you have one where the suspect is actually alive and well, and being questioned, I'm sure, at this hour and will undergo due process, the full legal system. And we will find out a great deal more about his motivations that led up to this horrific day. Martha.

MACCALLUM: And there he is in a video being taken from the hospital in a hospital gown, and into the arms of law enforcement for the questioning that you've just discussed. Trace, thank you so much for tonight. So back again, Bernie Kerik, former New York City police commissioner with a brand- new look, Bernard, as we take a look at the video that we just got in. This is of the Florida school shooting as police entered one of the rooms. Let's take a look.

MACCALLUM: I mean it's just chilling, right? These poor kids are all sitting in this room, and the police enter and they ask everyone to put their hands in the air.

KERIK: Right.

MACCALLUM: One of the things that it also appears happened here, Bernard, is that he left the building. And it sounds like he may have snuck out with a group of students, and that's how he got away.

KERIK: I think it's premature to say at this point because he was gone for close one hour before they found him, but it could have happened that way. Listen, he pulled the alarm, I agree with what Tony said earlier, this kid had a plan, he knew where he was going, he knew what he was going to do when he got there. He knew his escape route. You know I'm glad that they got him, and I'm really glad they got him alive, and they can get access to all of this information. But the more I hear, you know, your correspondent just talked about this order where if they saw him with a backpack coming to school, to notify the school because he -- you know, they were fearful of what may be in the backpack. Well, at that point, if you see all of these stuff online with the weapons and the knives and talking about bombs and all of this other stuff, are you not notifying the authorities that somebody may want to check the guns, take the guns? I don't know. You know, that's one of the things -- look, I'm all for the second amendment privilege, but in cases like this where you have people that have clearly had mental instability, OK, it's time to get rid of the guns.

MACCALLUM: I mean, obviously, he was on the radar of so many of these kids. They've said he was showing us -- as we were saying before in terms of a warrant, what more do you need than someone who is showing, this is what I have and talking about carrying out violent acts? Can you get a restraining order? Can a school get a restraining order from somebody like this and say, you know, you can't be 5 miles within the property, or mile, whatever it is?

KERIK: Martha, a restraining order wouldn't have stopped him from coming to the property. But each state has varied gun laws, right? And what you need to have to buy a long arm, a shot gun, a pistol, some states are easier than others. New York State, New York City is extremely difficult, like I said. If this guy was in New York City, have all stuff online? I can promise you within an hour there will be New York City detectives at his house grabbing all of this stuff. Why it doesn't happen in Florida, I don't know. It's something they've got to look into.

MACCALLUM: Certainly is. And what about the responsibility? We're hearing so much lately about the responsibility of social media and all of these companies, right? So if someone is sending violent images and talking about violent things on one of your platform, what's the responsibility?

KERIK: Well, you know, we have flagging mechanisms now for terrorism, right? You know, the terrorist chatter, you know, ISIS chatter and all these other stuff.

MACCALLUM: This is terrorist chatter.

KERIK: This is, in my opinion, this is terrorist chatter.

MACCALLUM: He's a terrorist.

KERIK: He's somebody who wants to do mass casualty, mass damage, death and destruction and all this other stuff, talking about the Syrian resistance. This is definitely something they should have been looking at. And I hate the Monday morning quarterback, this stuff, but, you know, as you get into it and speculate, but based on what we've seen already, there are problems that people miss.

MACCALLUM: And do you think that these social media companies have any responsibility to be stronger on this front?

KERIK: Well, you know what, personally, yes. Personally. You know, the first amendment rights and, you know, what congress lets them get away with, that's another issue. That's a long issue to deal with.

MACCALLUM: Bernie Kerik, thank you very much, former New York City police commissioner, tons of experience. And we're glad you're here tonight. Thank you, sir.

KERIK: Thank you.

MACCALLUM: We're going to take a quick break. We'll be right back with more of The Story.

(BEGIN VIDEO CLIP)

UNINDENTIFIED MALE: As soon as my mother told me I got very, very worried about him because he's my brother and it's Valentine's Day, so this shouldn't be happening.

(END VIDEO CLIP)

(COMMERCIAL BREAK)

MACCALLUM: These are the images of Parkland, Florida, today, on a Valentine's Day that turned out to be an awful tragedy. For 17 families who are waiting for more tonight in terms of information about what happened to their loved ones that they've lost. And you see these people's family hugging and spending time together. And we wish them all well tonight. Tucker Carlson is coming up next.

Copy: Content and Programming Copyright 2018 Fox News Network, LLC. ALL RIGHTS RESERVED. Copyright 2018 ASC Services II Media, LLC. All materials herein are protected by United States copyright law and may not be reproduced, distributed, transmitted, displayed, published or broadcast without the prior written permission of ASC Services II Media, LLC. You may not alter or remove any trademark, copyright or other notice from copies of the content.