is "nightline." >> tonight, how social media turned into a gateway to danger for a 13-year-old girl. >> i think that's why she to facebook. someone to give her attention and make her feel loved. >> new details from prosecutors tonight about the killing of a virginia middle chatted with her alleged killer on an app used by millions of american kids. plus -- there's a star the biggest game of the year for advertisers. on my cell phone >> they're paying a fortune to grab your attention for 30 the super bowl. >> just wait till you see our caucus.

caused a civil war -- >> the mystery inside the taco ? >> tonight the strategy behind a $5 million super bowl ad. but first the "nightline 5." >> let's give theseliquid gels and go. >> these liquid gels are new, mucinex fast max, max strength and fights mucous. let's end this. >> your baby's chubby hand latches onto your fingers so hard it's like she's saying i love hy aveeno's oat formula is designed for your baby's sensitive skin. aveeno, natural beautiful r one in just 60

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tonight we begin with the shocking crime that landed two virginia tech students behind bars.idnapping and murdering a 13-year-old girl. now we're learning new details about how they allegedlyng step by step plot to end the girl's life with chilling detachment. abc's eva pilgrim takes us inside the case. >> i never had one of my friends reporter: she was the sweet virginia middle schooler found murdered. tonight the details of nicole lovell's short life and gruesome death coming intoth new concerns about the dangers of social media. >> she seems like she was a nice girl. any understanding of why they behalf made fun of her?. just because it's middle school. >> reporter: nicole faced terrible medical problems as a he age of 10 months old, colie received a liver

fading, she was older, making connections on social media. >> that's why she started going to facebook. someone to give her attention, make her feel aking that awkward transition from childhood to young adulthood and her friend says she was meeting men online. >> i found out she waswas over the age of 18. you could tell he was way too old. >> reporter: shortly after, she says, another mysterious man. january 27th, nicole climbed out her bedroom window carrying only her phone and a minion blanket. >> i have had it to right here withhat this little girl is somehow responsible for all of this. what does she know about flirtation and dating the girl was lured out holding on, clutching on to her binky, her minion blanket. >> reporter: the police say she snuck away to meet this mann't she have trusted him?

star, good-looking, successful. >> i realize in the moment that i am doing things thatish they could be doing. >> reporter: he'd been on television. >> yet i still have goals for myself because there are people who are better than me. and i will personally not stop until i reach my peak back. soon almost 1,000 volunteers were searching and authorities scoured for leads until they were able to track the last nicole's phone leading them to eisenhower. >> the investigation led us to 18-year-old david e. a tech student. >> reporter: with eisenhower in custody authorities soon locate nicole's body, 80 miles away in north carolina. it's about two miles from a homeextended family. >> i'm sure that it's something nicole's family would like to know, why did she have to end up here,condition, discarded in the manner she was? >> reporter: the investigation leading authorities to identify and arrest what they say is an

natalie keepers, charged with helping eisenhower dispose of the body in these woods. >> i'm assuming that it was dark and they may have thought they were further away from the road than they actually are. because there's no lighting out here. >> reporter: prosecutors allege keepers also helped eisenhower plan the gruesome murder,or weeks, they say scouting locations, and even buying tools. when police showed up to talk to keepers, prosecutors say sheo warn eisenhower, texting him "police." it was then she allegedly told fbi investigators eisenhower le and put her body in his lexus, keepers allegedly saying she was excited to be a part of something secretive and special. >> that's really a stunning a great deal of callousness about that. she and eisenhower discussed how the murder would be committed,girl's throat, as though they're talking about an object. >> reporter: retired fbi

saying this is ah multiple motives spelling disaster. >> there's synergy that came together that made this a very lethal pair. >> a very preliminary the cause of death is stabbing. >> reporter: for nicole's mother, it's too much to bear. >> her favorite color was blue. was a very loveable person. nicole touched many people throughout her short life.part. >> reporter: while authorities wait for the results of an autopsy they have concluded that nicole was using a messaging app communicate with eisenhower, raising questions about possibly dangerous encounsay kick is a devil for young children. it's like a free ability to text. anything you want. parents can't see the phone any of these anonymous apps are popular

>> you can sign up as anybody you want to be. it really becomes a private for some of these pedophiles. >> reporter: here's how kik works. download the app for free, add any name and any photo, send messages, and you don't even need texting service. >> parents sometimes take away these data plans thinking that, well, the child has abused it. but they only need aal to be age ble to communicate. >> reporter: abc reached out to kik who told us kik cooperated with the fbi for their investigation, kik with law enforcement to combat child predators anywhere in the world, even upon provision of a court order or emergency situations like this one. sorted bycation, by school, by age. how do you keep your family safe? >> the first thing parents need to do is set ground rules. secondly, know the technology, know how the parental controls third, they need to talk to

conversations about safety, so that kid when it comes time makes that safe and smart decision. >> reporter: and it's not just are many other apps kids can use to hide things from their parents. blogger liz gambenert how easy it is to hide incriminating photos. >> when you open it up and i type in my password and hit the's a hidden photo album. >> reporter: sending photos as easy as point and click. kid swap the files in apps such as snapchat, kik, yik yak, whis aking sharing large numbers of files fast and easy. >> kids will always be savvier than mom and dad, one step ahead of us, that's the nature of the eporter: nicole's friend carrie said she tried to tell an adult months ago after she noticed nicole was older man. >> i went to the officer at my school.

piece of paper and handed it to the blacksburg police department denying she alerted the officer about eisenhower saying, had a student or even nicole herself reached out to him in advanceearance about anything that could cause concern, he would have act the on it through the appropriate channeled schannels. >> did you no. i think if he would have done something he could have seen the guys on her facebook and he could have stopped all of this. >> reporter: nicole's family filing into court wearing blue hour before her burial, mourning a daughter gone too soon. >> a preliminary hearing for eisenhower has been scheduled for march 28th. next, owl of advertising. how madison avenue is rewriting the play book book on how americansgest sporting event of the year. counting down to tomorrow night's big gop debate right

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t's the nfl's biggest game of the year but it's also the highest-rated show on television, making the super bowl the perfect marriage of sports and media.ted to generate, get this, $377 million in advertising revenue. and while the stakes are high for the teams on the field, they for the teams and the ad agencies across america. abc's nick watt takes us inside some of the nation's most creative minds.r: sunday night field --

>> reporter: men in tight pants, hard ield in commercial breaks there's another just as intense. >> america has seen the light! >> and there's a butt in >> this behind the scenes battle is between women, men in beards and industrial space, doodling. "madman" was then. >> this is the greatest advertising opportunity since the invention of cereal. >> reporter: this is now.tle deploying every weapon from amusing it girl -- >> it's not too big. like you could handle it. you used to call me on my >> reporter: to canadian rappers. >> these changes don't ruin the song at all. >> reporter: recently deceased rock stars. star man hletes. down. >> really?

and septuagenarianwith socks on their hands. >> there are those who expect more. >> reporter: every slot costs roughly $4.8 million for the air time alone. it's up years. why? because over 110 million will watch sunday night. the highest-rated show on >> you're talking about an audience that is larger than any other audience out there. >> reporter: and then the bragginge never been a professional athlete but i know what it's like to be a professional marketer. raisinggest game of the year. >> reporter: the way doritos does it, competition, a $1 million prize for the best amateur submissions which they air sunday night.the three finalists. me and the dog the stars in this one. >> the schtick is dogs like

>> competing with huge ads created by mega companies, we don't have all that access, so we've got 30 seconds to make people relate laugh and remember it. >> relate, laugh, remember. >> yeah. >> reporter: for the ad-obsessed, youtube offers their ad blitz channel where fans can watch and votevorite commercials. >> what is up, guys? >> reporter: videos from social stars like millennial ava of the draw. >> it's about the concept. no matter if you're putting a ton of money mind it or one little blog camera, peopleo to whatever they want to watch. >> reporter: the big dogs also leverage social media, leaking teasers, trailers, sometimes the actual commercials, online ahead of time. it's now the norm. comes to game day, if you've seen this commercial already you're going to say, wait a minute, everybody, stop, put your beers down, check this out.

>> doors will open to reveal the team kia. their walken kia spot is already racking up hits ons that? >> the new kia optima. >> reporter: in manhattan, team bud light airing their offering >> so far, so good. on track i would say. >> america has seen the light! >> and there's a butt in front of it! >> reporter: now to deutsche in l.a.y intentionally leaked this gem for volkswagen. and set a trend. it out there before, why not keep it for the super bowl? >> we thought, if there's that much thrust irst and hunger for this to them, just lean into it. so that blew up huge. then the next year, everybody

>> reporter: but this team taco bell. and taking a different tack. >> the toppings would stay in better if we flipped tandard now for brands to drop their ads early. everything's out of the bag sometimes a week, two weeks spot even comes out. but this year taco bell and i think a lot of advertisers this year have chosen to hold back.eople are showing everybody what they've done before super bowl sunday. >> you're holding it upside down. >> really? >> reporter: there are teasers.lly does not know what he's advertising. >> taco bell won't talk about the product they're launching until sunday. they won't show the commercial until sunday. everything's a mystery. top secret can a taco bell product be? >> you can preorder the product, 700 people as of this morning preordered something they don't know what it is. >> advertising. you're selling something to people they don't know what it is.

you already want to eat it. >> do you know what it is? >> no idea. >> what can they do to a taco? >> reporter: who wins this and arguably the bigger battle sunday night? it stands to critics, reaction, and the looks on friends' faces. >> looking around the room seeing people -- >> yeah, yeah. >> if they're actually -- >> hey, good, that's great, brad. >> that's not good. >> not good, that's the fake one. then there's, "that was good!" that's the one i'm lookingot something for you, girl. knowledge. anywhere you want it. >> reporter: i'm no stranger to the ad game. we made this for "nightline" a year long story as to why. anyway. to get an idea how this multi-million dollar creative process begins, a challenge. lt client. we have a tv show called "nightline." you need to think of a super bowl commercial for our tv show. ideas, come on.

>> "nightline" is better than any other show? >> we are better at topical news but funny. >> do you want to tug at the heart strings? >> no, i don't want anyy stuff. i want belly laughs. like smutty bell -- laughs. >> if you guys were the first to create an- nontraditional icon, like maybe a talking cat. >> reporter: stay with me. >> do you have an enemy? >> james corden. >> seth meyers and james>> so take down seth meyers. >> fall asleep to us instead. >> reporter: is they nowhere near as inspiring as christopher walken with a sock. here's why. we'd probably love to come up with a great super bowl commercial for you for "nightline" right at the table today -- >> it would take eight, nine mont of every agency is and forever has been to upstage this. the commercial that started all

battle back in 1984. apple. can anyone trump it this year? >> we shall>> reporter: schumer perhaps? >> that's why we're forming the bud light party. >> reporter: walken? >> pizzazz! >> war hawk, this is good! don'tt it is! >> reporter: or whatever it is in that taco box. i'm nick watt for "nightline" in los angeles.nting down to the battle for the granite state. we'll have a preview of tomorrow night's final republican presidential debate right here at abc before tuesnew hampshire primary. (music) woman: i' ll never remember all the projects, presentations, or meetings i gave up my nights for. (music'

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finally tonight, the race he stakes couldn't be higher in the republican contest. donald trump will be front and center for their final debate moderated by our own david muir and martha ving us a sneak peek tonight. >> hey, good evening. the excitement is mounting here at st. anselm college in manchester, new hampshire, as our abc news crew finishing touches on our debate stage. top three candidates -- donald trump, ted cruz, marco rubio -- will be taking center stage here if there's one thing we can count on it's some heated exchanges. all the candidates are gunning for momentum. just ahead of the crucialary on tuesday. everybody wants to make their

move forward. but it may be the last chance for some. >> thank you, martha. david muir will moderate that debate tomorrow night at 8:00 eastern, 7:00 central time, right here on abc.ident george h.w. bush who said, if anyone tells you america's best days are behind her, they're looking the wrong way. thank you for watching abc news. tomorrow. as always we're online on our abcnews.com. good night, america.