♪ do you know where the shooter is? >> tonight on "nightline," those horrifying moment playsing out in a florida high school. teenagers running for their lives as we learn at least 17 are dead. >> we were just, like, praying, and crying. i don't know how we're alive. >> a gunman rampaging through the halls. >> oh, my god! >> students hiding under desks and in closets. swat teams swarming the scene. students scrambling to safety. forced to abandon their backpacks. search for weapons. lucky survivors reunited. now expelled student in custody.

his obsession with guns and the latest in the investigation. "nightline" will be right back.

good evening. thank you for joining us. another horrific school shooting echoed across american, 17 killed in parkland, florida, a

city listed just days ago as one of the safest in the country. tonight we hear new detail s about the suspect who is now in police custody. >> we could see the panic from a distance. frightened. >> reports are just coming in. don't have a lot of didn't kno of us feared the what. >> there's an active shooter situation situation in south florida. >> [ bleep ] oh, my god! >> that rapid roar of death and dieing. in another american school. >> does he know where the shooter is. >> we don't know but we're heading into the building. >> the first 911 calls came just before marjory stoneman douglas high school led out for the day. police fbi and atf all descended on the scene. >> we can't get hold of her. >> have you called and texted and nothing has come back.

>> girlfriend got shot we heard. >> there was panic. confusion. parents desperate to find out had their child survived. >> it's devastating. i'm sick to my stomach. >> a line of ambulances in place of the school busses. >> we were just praying and crying, and i don't know how we're alive. >> hours go by. students finally reunited with their family and by evening 17 dead, 14 injured, and former student nikolas cruz who can stole so much from so many. >> come to the conclusion this is absolutely pure evil. >> students detailing those traumatic moments from inside. >> all we heard was the gunshots. >> we heard the gunshots and hid in the tennis courts. >> talking about what they did as gunfire echoed in the

hallway. >> heard le a garbage truck banging. we hear boom, boom, boom hear screaming and we jumped under hi teacher's desk. swat teams searched the perimeter. >> moner titoring the subject. he went from the third to second floor. may have a gas mask on. >> students barricading in sro they could hide. >> need everyone down. >> as officers go room to room. >> put phones away. >> some recording disturbing videos of the mayhem many texting their parents. >> she keeps telling me be safe stay away. i'm telling her no i'm your mother i'm not staying away. >> outside high schoolers

streaming out of the building hands over their hands for safety. just after 3:00 p.m. the shooter is still at large. >> white male. burgundy shirt wearing black hat or long black pants mixed in with a group of students running west bound. authorities said he got out of the school by blending in with others who were trying to escape. >> it's not uncommon for thieves, like robbers, to try to blend in with the crowd and try to escape. somewhat unusual with mass shooters because vast majority of time they kill dhem selves or force law enforcement to kill them. >> students outside, breathless, heart wrenching reunions, others waiting for answers, some student and staff unaccounted for.

>> what did she fell you. >> she's crying. can't say anything. she's crying a lot. >> this student recalls seeing teacher shot. >> we saw his body for like 30 minutes. we were just like praying, and crying and, then the police came and we just got out. >> this is the day we prayed would never be here in broward county but we're going to deal with it as a community. >> around 4:00 p.m. the alleged gunman taken down in this video, sourced identified him as 19-year-old former student nikolas cruz. >> he was a former student of douglas high school he got expelled, i don't know the specifics. >> the school represented something to the shooter. this is not the first time this has happened. think of adam at sandy hook who walked into

elementary school he attended years before, because there was something about that school that he wanted to destroy. sadly, he did. >> tonight new information about at ledged shooter, a family member telling a brb c news, cr was adopted with his younger brother both parent noise deceased. a former class mate called him quiet. that he had a interest in weapons. >> i knew >> last year had a lot of conflicts in school. got in a fight with one kid and wasn't allowed to bring his backpack because they found bullet casings in it. >> i told my parents last year every week i was scared this kid might go something. >> if you take somebody's access to firearm and the fact they talk about fighting or have been in fights now you stae pieces t the dots of an individual who

may have predisposition to commit an attack like this. >> authorities say the suspect used an assault rifle and began shooting outside before continuing inside. >> he had multiple mack zeens. magazines. and one ar 15 rifle. >> sound liekz a fire alarm was tripped. big question will be whether th alarm, if that was done to get the students to come out of the building and then the suspect was then starting to shoot at the innocent students coming out that would indicate there was planning on his part. >> today's shooting marks the 18th school shooting this year in a nation with average of 300 mass shooting each of the last three years. that's at least four shot in each incident. too soon since the mourning of las vegas those that were killed

in the church in texas. >> as a parent it scares me to death that this body doesn't take seriously the safety of my children. >> connect senator chris murphy who represented the state sandy hook happened five years ago was on the floor when news broke about today's killings. >> it only happens here not because of coincidence, not because of bad luck, but is a consequence of our inaction. >> president trump also responding, tweeting no child, teacher, or anyone else should ever feel unsafe in an american school. >> no parent should ever have to send their kids to school and have them not return. that shot not happen. not in parkland, not anywhere in this country. >> school shootings are no longer new in america. each one still numbering. we send our children to school to learn, not to die.

next, how communities across the country are preparing for the worst. schools and law enforcement running active shooter drills. ♪ life goes on, yes, life goes on... ♪ i've always wanted to share a special moment with my mom. i think surprising her with a night ski trip would just be the biggest gift i could give her. let's make that happen. she's gonna be so excited. ♪ take me where i want to be. ♪ ♪ let me dream, oh, let me dream... ♪ if you could see your cough... it's just a cough. you'd see how often you cough all day. and so would everyone else. robitussin delivers fast, powerful relief to fight your cough in 12 hour shifts. robitussin 12 hour cough relief, because it's never just a cough.

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♪ ♪ there are two types of people in the world. those who fear the future... and those who embrace it. the future is for the unafraid. ♪ ♪

♪ school shootings like the one in florida today are becoming so common that many schools across the country are actually training for them, drilling students where to go if they hear gunfire and how to spot when a shooter is out of ammo and in some cases staging dress rehearseals.

>> where's the shooter. >> we don't know but we're running in the building. >> today the unthinkable happened again. >> i'm sick to my stomach. >> unfolding this time at marjory stoneman douglas high school in parkland, florida. >> i jusheard gun sohots.

this is a terrible day. for united states. >> events like this continue to happen. so american law enforcement and teachers are getting to be experts in responding to deadly incidents like this. >> minutes and seconds matter because so much damage can be done by the type of weapons that are available in our country. semi automatic high-power rifle. the capacity to hold more bullet in the magazines creates this dynamic of multiple frtragedies >> today's ranks among the top five deadliest to date. >> now they're doing fire

drills. >> i'm going to kill everybody nobody's getting out. >> some go as far as covering student in fake blood all in an effort to make ttihe >> attention. this is a drill. we need to lock down. >> in 2014 we embedded at sky view academy in colorado as they went through the standard lock down drill. >> please go behind my desk. >> the teacher locks the door and pulls the shade. everyone's told to keep quiet. >> it's kind of squary. >> yeah. >> the kids huddle quietly. >> do know why they do this did drill. >> to practice in case anyone comes here. >> do you scares students. >> we do but we practice enough that we hope that students are and staff is getting used to the idea. we have to. >> how long do these go for. >> fivege we've

had. >> teacher holley carpenter supported these drills she's a graduate of columbine high school. >> when you look at those kids are you always thinking someone could come take their lives. >> no i look at those great the lucky i am to teach them, and i up. >> that day changed her life and is why she take these drills very personally. >> i always get a lump in my throat it's not about flash backs of columbine it's about the thought of anyone even wanting to hurt the kids. >> sky view academy doesn't just do the basic lock down drill while we were there the teachers were getting a new method of training. >> nobody's getting out. teaching everyone not just to

duck but to respond. >> active shooter training is the new normal and because these incidents are repeating themselves, escalating and we're learning lessons from failures in the past. >> how did you feel? >> lots of adrenaline. >> former swat team member has responded to active shootings for real. >> this open. what's that mean? >> he's teaching them how to recognize when shooter is reloading his gun. >> he's out. right. >> and teaching defense tactics. >> there we go. good. good. >> how to take down a shooter. first responders do too back in 2016 night line embedded with the douglas county sheriff's department. in a scenario this time more complicated. shots fired.

hostages strapped to explosives and multiple schools on alert. deputy and first responders race down the stairs and hallways not knowing how many gunmen there are. just as things are heating up at the high school another call sends deputies to a different call up the street. >> possible shooter at the middle school. >> two deputies head in alone. no time to wait for back up. inside helpless victim. one student chained to a bomb. these cops know their first priority is to eliminate the active shooter. in this scenario hold up in a first floor bathroom. drills such as this are no doubt good practice for the professionals. but is it fair to expect teachers and students to put

themselves in harm's way. >> teacher or student really going to be able to take down 200 pound gunman. >> let's find out. joe is about 220. pick out anyone in the crowd and see. >> let's do it. >> so we got holley carpenter in her columbine sweat shirt to do it again. >> this time the guy's going to fight back. >> this time the gunman resisting her effort to disarm him. she's glad to have strategy she can line. >> how's that feel? >> really good. >> this active shooter drillend this time everyone arms themselves with a tennis ball but in real life might well be a hole punch or desk, chair, tony zych airy, this time it's the active shooter whose the sitting duck.

would this works if the if this class full of kids, hard to know. but unfortunately with every incident like today in parkland more and more communities figure better safe than sorry. >> our thanks to you david we'll be right back. where's frank? it's league night! 'saved money on motorcycle insurance with geico! goin' up the country. bowl without me. frank.' i'm going to get nachos. snack bar's closed. gah! ah, ah ah. ♪ ♪ i'm goin' up the country, baby don't you wanna go? ♪ ♪ i'm goin' up the country, baby don't you wanna go? ♪ geico motorcycle, great rates for great rides. i ...prilosec otc 7 years ago,my doctor recommended... 5 years ago, last week. just 1 pill each morning, 24 hours and zero heartburn.

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♪ finally tonight, america's late massacre occurred on a day designated to celebrate love, valentine's day, maya angelo said if you have if you only have one smile in it, give it to people you love, adding a hug on this day, wouldn't hurt. as always you can follow us on "nightline" facebook, thanks for the company, america, good night. night.

you brought me flowers. see? your, uh, keen powers of observation are what make you such a great cop. thank you. that is really sweet of you to try to cheer me up. well, i hope i succeeded. but it's not the only reason why i brought them.

-it's not? -mnh-mnh. what's the other one? you really don't know what today is? mm. [ gasps ] what about your dad? yeah, he -- he went to bed early. ohh. and josslyn's at a sleepover. -mm-hmm. -mm-hmm. mike: just pretend i'm not here. i'll be as quiet as sister bilanda on good friday. wow! dr. munro! you look amazing! uh, uh, thank you, amy. who's the lucky lady? please say someone besides ava jerome. [ chuckles ] you're still here. uh, yeah. well, the alternative is going home and celebrating valentine's day by myself, so... [ exhales deeply ] i know what that's like. ...in the apartment building that michael is selling