this is "nightline." >> tonight after the nightmare, new police body cam footage from the las vegas massacre. survivors fighting for life in hospitals. stories of heroism and horror from the heart of the attack. >> you were filming as you were running for your life. >> now inside the killer's room. a camera rigged in the hallway, possibly to detect police. and the shooter's girlfriend, now a person of interest. from weapons of war. we're at a gun store in utah that sold firearms to the shooter. >> a feeling of guilt. >> how an departmenter can make

a gun fire like a machine hill. an e.r. doctor who traded children from sandy hook. >> this special edition of "nightline," massacre in las vegas, will be right back.

good evening.

yesterday we were a nation in shock. reeling from the worst shooting in modern american history. tonight we're coming to grips with it all. for hospitals it means treating the wounded. for the survivors, for those who lost loved ones, it means finding a way forward. you covered sandy hook, orlando, what is it like in vegas? >> this community is coming together in grief and pain but also with a real sense of love and gratitude. you and i talk about there all the time. amidst the carnage and the cruelty, we find uplifting stories. today i got to spend time with a family and watch the magical moment when they had an opportunity to thank their guardian angel. >> this is donny, the firefighter who was with your mother. >> this is the first time since that fateful night that she is seeing the man who helped save her mother's life. >> there's my angel. >> my mother is alive because of

you. >> she is face timing with the firefighter don matthews who happened to come across her and her family and told them they needed to go. >> i promised your daughters i would be there. >> and you kept your promise. i knew you would. >> her mother shot in the torso. matthews insisting that he stay with her instead of faith and her sister so they could flee for their lives. >> just trying to do a small part. i really wanted your daughters out of there. >> tonight the sisters are home with dad as their mom recovers from yet another surgery. >> it was a mother's day present. >> she's having the time of her life. >> the time of her life. >> the route 91 harvest festival was supposed to be a celebration. just after 10:00 p.m. -- >> i got another text. the next thing i saw was omg. >> he unleashed gunfire on a

crowd of 22,000. >> i saw that i was covered in blood. my first reaction was where is it coming from? and i looked over. and i saw a flap of my skin that had just exploded. >> but page said she didn't even feel the pain with a more terrifying responsibility. >> i looked around to see who was with me. my mom wasn't just laying there like we were. she was still in hface down in grass. >> you grabbed my sister's sweater. >> right and i put it over her shoulder to stop the bleeding. >> her mother was eventually taken to the hospital by volunteers. and she is beginning to make recovery after two surgeries. these rethe faces of those we lost that night. people like this woman from las vegas. a mother of three boys. denise from west virginia, married 32 years to her husband. she died in his arms.

stacee etcheber from san francisco. her husband was a police officer who told her to run. >> we have an active shooter. >> the country music fans trapped for about ten minutes of terror. that has so far left 59 dead and more than 530 injured. >> 22,000 people were gathered inside the barricades. and this made the effect of shooting fish in a barrel. >> in this newly released body camera footage -- >> stay down! >> law enforcement struggled to make sense of the chaos. and these the terrifying moments that play out in front of photographer brenden o'neill's camera lens. >> you were filming as you were running for your life. >> he was backstage during the

set and ran after hearing the gunfire. >> we ran around the stage and went around the cop car. right then, bullets were coming right here. >> we had no idea. there were people in the convenient you've with guns. no one knew where it was coming from. >> you can their confusion. people not sure whether to run or hunker down. >> you have to go! [ bleep ]. >> stay down! >> then a woman near them. >> her friend is hysterical. oh, my god, she's shot, she's shot. >> my friend and a couple other

people picked her up. brought her over to the police vehicle to get her out of harm's way. and she just wasn't moving. i don't think she made it. i don't know. >> you're getting emotional even thinking about it. >> yeah. >> las vegas area hospitals would receive the hundreds of wounded including sunrise hospital. the veteran e.r. doc led the triage effort. it was everywhere. heads, neck, chest, abdomen, arms. >> today we talked with justin burton and his wife jay just after being discharged. he said his spinal injury is unhe said rabble. >> so would you have to bullets lodged. >> they said it would be more harm to remove the bullets. >> increditably, list doctors said he'll make a full recovery and today he's going home. >> i'll going to do it. >> it is difficult for him to

sit but this is a milestone he is eager to reach. the bullets were designed to do maximum damage. something the shooter may have considered. >> the world has changed. who would have ever imagined this situation. >> authorities staying shooter sgheekd the mandalay bay resort last thursday with an arsenal and an ar 15 seen through the battered doorway. that gun outfitted with the scope typically used for hunting and a bipod. >> i see the shots! >> patrol officers he heard the shots, entered the stairwell and evacuated nearby guests. a brave security guard moved in closer. >> he was advancing toward the room. the suspect went in and struck him. >> as s.w.a.t. teams approached the 32nd floor, the shooter may have had eyes on them. >> there were two cameras located in the hallway.

so the suspect could watch as law enforcement or security approached his room. and there was another camera placed inside the room door people hole so co-see down the hallway. >> flight on the service cart. just tonight, abc news obtained these images from the room after the shooting ended. there could have been over 1,000 rounds of ammunition in the room. in this chilling photo, the killer's lifeless body on the floor. authorities naming his girlfriend as a person of interest. especially after the discovery by police of so many womens. so much ammunition and explosives at this home they shared in mesquite, nevada. >> she had to know something. at the very least question him, where are these womeapons comin from? why do you have them? >> she worked as a hostess on enter teenage high rollers like paddock who routinely gambled

more than $40,000 at a time. what was still under clear, the killer's motive for committing now worst mass shooting in modern american history. with so many feeling so powerless, there have been tangible ways to help. >> take a look at how many people are out here. it keeps going. >> hundreds waiting for hours to donate blood. and a fundraising website to support victims raking in over $4 million in just one day. >> as the story from sunday night continue to be said told, there's a common thread. hero i in the wake of unspeakable terror. >> i saw a girl, hit in her leg. i helped her back up. as i was helping her, i got hid in my elbow and mid section. then a hero saved me and threw me in and took care of me. >> do you know his name?

>> i wish i did. >> and he came all the way to the hospital with you. >> yeah. he saved my life. >> if he's watching this, what do you want to say to him? >> i can't thank you enough myself gratitude is unmatched. and the whole hospital team as well. saved my life, literally. >> our thoughts are with all of those in need of healing tonight in las vegas. >> a gun store that sold firearms to the alleged shooter. what that owner is saying today. ♪when you've got...♪ ♪...nausea, heartburn, indigestion, upset stomach, diarrhea!♪ ♪nausea, heartburn, indigestion, upset stomach, diarrhea!♪ here's pepto bismol! ah. ♪nausea, heartburn, indigestion, upset stomach, diarrhea!♪

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today is a dave hard questions and hard realities. how could one man destroy so many lives in a matter of minutes? pass through world undetected up until the day he brought havoc on a nation. could the damage have been minimized? and as a country, where do we go from here? here at dixie gun works in utah, the owner chris michael woke up shocked by the news of the las vegas shooting and the identity of the alleged gunman. >> i recognized his name. i recognized the face. and i remembered exactly that he was a customer. i remember him coming in and purchasing a firearm through us. >> michael says he sold paddock a shotgun in february. >> everything was a normal purchase by a normal person. there was nothing that stood out. >> but now he is struggling with the knowledge that a gun he sold may have been used for the unthinkable. >> what if, could have, would

have, should have, all those things keep falling into place. is there something i could have done? >> today abc news is learning more about the fire articles. today, guns were found, articles, shotguns, pistols, purchased in four different states. police say one of the weapons used in the las vegas attack, modified like a machine gun. >> this is classic wmd. a weapon and a man of mass destruction. >> sunday's shooting brings a fierce debate over gun control. >> this morning we have children without parents. and fathers without sons, mothers without daughters. we lost two police officers. >> last night, jimmy kimmel.

>> i don't know why our so-called leaders allow there to happen. or maybe a better question, why do we continue to let it happen? >> most leaders divided. the pro gun rights republicans say the things they so often say. >> and i think it is pre mature to be discussing legislative solutions if there are any. >> it is the only issue that i'm aware of that has that kind of response. something bad happens. the immediate response in congress is it is too soon to talk about it. >> if not when the country is focused on it, what would be a better time to talk about these issues? >> in more familiar language from pro gun advocates. >> he was a sick man, a demented man. >> i don't think there's any question if the shooter was an undocumented immigrant on, a refugee from a majority muslim country, or even someone with a muslim name, the response of the

president would be quite a bit different. >> pro gun control saying what they say. >> it is time for action. >> we can say enough is enough. >> chris murphy, the democratic senator from connecticut, has been pushing gun control since the tragedy of sandy hook. today not surprised by the pro gun response. >> a tried and true tactic to tell advocates for change that we can't talk about change. >> in las vegas, ripping off scabs not yet healed from the story we have heard and told so many times before. >> i don't know if the people are still out here. >> this is a club nobody wants to be in. >> she lost her only son christopher 16 months ago. one. 49 killed at the pulse nightclub shooting in orlando. she became an activist for gun control. intent that orlando's tragedy would not repeat itself. >> we can prevent these

massacres. my son's killer legally purchased an assault rifle. >> a mother resolved that her son would not die in vain. >> it is so unfair that he was stripped of his future. >> christine is not alone in sure the attacks of the past are not forgotten and throws of the future are prevented. >> i am not a politician but i am a physician who is sick and tired of being reactive. reactive to the gun violence incidents. >> william is an emergency room physician who lives in newtown, connecticut. five years ago, he treated victims of the sandy hook massacre. 26 people, including 20 school children, gunned down. one of the darkest days in our nation's history. >> gut reaction. >> it was one of immense sadness for all those families. and the victims. i honestly could not physically

watch more than a few seconds of the tv. and then it turned to anger. i do know, i am passionate that events like this, in my estimation, preventible. >> he sees gun violence as a public health issue. >> you can own a gun. why do you need to own a gun can shoot hundreds of bullets in a minute? what can we do to mitigate all these deaths. >> through conversation and policy, he hopes the country will get on the right track. >> after this, can we at least talk about this. which is a huge cultural shift. >> obviously we have a lot more work to do in front of us. we have to do better as country. >> do you think we will? >> i think we will. >> tonight in utah, chris michael says more restrictions of banning firearms are not the

answer to the great debate on guns. >> there's not a rule out there, i could be wrong, that could have prevented this. when bad people want to do bad things. hopefully it will prevent future tragedy. >> i believe i'm at the front lines. i'm the guy at the very beginning dealing with anybody who walks in. the good person or the bad person. i'm supposed to be weeding these people out as best i can. the checks and balances for the paperwork they go through, that the database looks you this. i'm still the first guy here and i'm the last guy. >> and we'll be back with more from las vegas. with my moderate to severe crohn's disease i kept looking for ways to manage my symptoms. i thought i was doing okay. then it hit me... managing was all i was doing. when i told my doctor,

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it's been a trying few days in america. particularly las vegas. >> reporter: you know, we met a lot of people today whose bodies are shattered but whose