on this sunday night, warning signs. new details emerge about the teenager who went on a shooting rampage at his colorado high school. what fellow students are now saying about his behavior before the shooting. search for answers. the body of a former nfl star is exhumed. a new effort to determine what triggered a tragic murder-suicide a year ago.

shoppers beware. how the apps you use to search for bargains are also being used to spy on you. and remembering peter o'toole. we'll look back at the famed actor's long and successful career. good evening. first the shot. then the shock. and now the hard ques there war? the question friends of the teen who opened fire in his denver area high school on friday are wrestling with tonight. 18-year-old karl pierson took his own life after storming into his high school and shooting a classmate, severely wounding her. now a friend of the shooter is telling nbc news that pierson had grown angry and had made threatening remarks about the teacher who police think was his prime target. nbc's ron mott spoke with a friend today.

he joins us from centennial, colorado work brand new details on this story. good evening. >> reporter: hey, lester, good evening to you. a darker image of karl pierson is emerging from one of his classmates who said he thought he knew him pretty well. they spoke last monday about pierson possibly coming back to the debate team. he said he scrunched down in the hallway when the shots rang in the hallway before breaking down when he found out the shooter was his friend, karl pierson. >> my first instinct is to want to defend him but i know that's wrong. it is indefensible, what he did. it is horrible. it is hard to process those emotions. >> i'm karl pierson at arapahoe high school. >> reporter: co-captains on the debate team weren't close friends but he felt close enough to help him. >> speech and debate was his life and the fact he was not there crushed him a little bit. it made him tense and angry.

>> reporter: it had been a stressful fall term for pierson. he had grown angry from losing his coveted spot on the team months ago which made the coach, the librarian a wanted man in pierson's eyes. >> karl and murphy did not get along. whatever it was escalated to a death threat. >> his intent was evil and his evil intent was to harm multiple individuals. >> reporter: police say pierson stormed into the school heavily armed, prepare to hurt many more than just one person. as he moved toward the library looking for murphy, he shot 17-year-old claire davis in the head point blank, eventually turning the weapon on himself. >> the karl that i knew was a good person but obviously the karl that came into school friday was not. >> reporter: the violence only added to the disbelief and pain in a community especially hard hit by deadly spree killings. columbine in 1999. 13 dead. a movie theater in aurora just last year. another 12. today colorado's governor echoed what many have expressed here.

>> what in the world is going on in the denver metro? >> god only knows. there is no rational explanation for it happening here. i'm sick of it. i've had enough of this. everyone in colorado has had enough. >> reporter: he said he has talked nonstop to classmates on friday hoping to make sure no one internalizes the trauma when help is all around. >> i did try to help him and i didn't get to him. and other people tried to help him and didn't get to him. and i think there are so many people in my school that were supportive of him but no one was able to get to him. at the end of the day, that's what happened. >> reporter: joel said he talked to a number of students and a number of students have gone into what he calls a shell. he is encouraging everyone to talk to counsellors and one another. in the two days since it happened, he said it has really helped him. >> thanks very much. a major new development involving a star nfl player who shot and killed his girlfriend and then himself last year. the body of kansas city chiefs

linebacker jovan belcher's body has been exhumed. they hope it will determine whether a brain injury was a factor. >> reporter: more than a year after the murder-suicide, his family still wants to know why. ordering the linebacker's body exhumed so his brain can be examined for chronic traumatic encephalopathy. he killed his girlfriend, the mother of his 3-month-old daughter. >> okay. they were arguing and he shot her? >> yes. yes. they were arguing. >> reporter: then in the parking lot of the chiefs' practical facility, shot himself. at the time his family mourned the man they knew. >> his kindness, humility, respect and gratitude for family and friends were steadfast. >> reporter: now they wonder if his years on the field could have damaged his brain. >> he had a lot of hits as a linebacker. probably including a lot of

concussions that went undiagnosed or unreported. >> reporter: doctors at boston university recently reported finding cte in the brains of 52 of the 54 deceased nfl players they tested. >> we know in many cases how this manifests itself. suicide, dementia, severe memory loss. >> reporter: last year retired nfl great junior seo committed suicide. his brain pathology confirm cte. in 2011, the bears safety shot himself in the chest leaving a note donating his brain to the nfl brain bank. it too showed cte. experts say a similar diagnosis for belcher may not explain everything. >> even if jovon belcher is bound to have cte, that doesn't mean it was the cause of the murder-suicide. >> reporter: but his family hopes it is a step toward understanding what led to the unthinkable. nbc news, new york. much of the northeast spent the day digging out from a

powerful prewinter storm that left a foot or more of snow in parts of new england after dumping seven inches yesterday on detroit and six inches on new york city. the storm is blamed for at least four deaths in traffic accidents. it also caused hundreds of flight cancellations. airlines are still struggling to get back on schedule. now to syria where the bloodshed and suffering from the nearly 3-year-old civil war shows no end. government air strikes today on rebel controlled areas in the northern city of aleppo reportedly killed 37 people, including 16 children. meantime, harsh winter weather is setting in, adding to the crisis. especially among the more than 2 million syrians who have fled. they include those in a refugee camp across the border in northern lebanon, just visited. >> reporter: a miserable winter in a devastating war. syria blanketed in snow. the fighting is relentless.

in battle-scarred aleppo, children, including some infants have frozen to death, according to an opposition group. families that fled syria have only flimsy tents of protection even where there isn't snow, it is still bitterly cold. each one of these makeshift tents are home to at least one family. and there are hundreds of camps like this. thousands of families. an estimated 1 million syrian refugees in lebanon alone. and they feel utterly abandoned. and desperate. mothers cling to children and grams for food vouchers. this one in northern lebanon, they're feeding 1,300. among them, 8 mold and her mom who escaped bombing. she left her husband behind, she tells me in a three-year war no one is winning, she cannot know when they'll be reunited.

she passes the free blankets. they're not for her family. they are for those visit in even colder conditions. she is gathering firewood to try to keep her six children warm. they have only one blanket to share. >> this is where you sleep. all of your family. there is no comforting her 2-year-old daughter. amnesty international said western leaders should hang their heads in shame for the pitiful help they have offered these people. while the war grinds on, the rebel fighters supported by the west are losing ground and refugees who look to america for help are losing hope. nbc news, lebanon. south africa bid an emotional farewell today to nelson mandela marking the end of a ten-day mourning. it was following a state funeral

held in the humble village where he spent most of his childhood. richard engel was there. >> reporter: it was the final stop on a long journey. where nelson mandela asked to be buried in the small village where he grew up. it was a grand state sendoff. but also a private farewell. in a massive tent by the mandela family graveyard, a few thousand invited guests, extended family, world leaders, old friends, prince charles among the mourners, oprah and richard branson. >> he went to school with bare feet and in the end he rose to the highest office of the handled. it is within each us to achieve anything we want in life. >> reporter: ahmed spent years jailed with nelson mandela. >> i have lost a brother. my life is in a void and i don't

know who to turn to. >> reporter: in life and now death, mandela's journey is the founding myth on which modern south africa is built. all across the country, crowds gathered to watch on large screens. >> these people were not invited to attend the private ceremony but wanted to participate together. at least watching on it a big screen to mourn the passing of a man and the passing of an era. south africa's current president, jacob zuma,ments criticized for failing to live up to mandela's moral standard. vowed to carry on the legacy. >> the long walk to freedom has ended in the physical sense. our own journey continues. >> reporter: and then at noon by tradition, when the sun was highest, the shadows shortest, he was let go. and south africa said nelson mandela was finally free.

richard engel, nbc news, south africa. president obama of course paid his respects to nelson mandela when he spoke at a memorial service in johannesburg on tuesday. you may have seen these photos released by the white house, taken aboard air force one on the way to south africa. president bush and his wife laura, secretary of state hillary clinton traveled with the obamas. official photo releases like these are not. >> reporter: now at the central of an escalating battle between the white house and the news media over access and image control. our white house reporter has more. >> reporter: this sumter president and his former secretary of state had lunch at the white house. a newsworthy event. the news media weren't invited in. only the one given access? the official white house photographer. >> we're the first eyes and ears for the public. if we're not getting access to the president, the public isn't getting access to the president. >> reporter: he calls images

like these pure prop ganld a. arguing the obama white house consistently blocks journalists from events they routinely covered in previous administrations. the most recent example, those photos of the historic air force one trip by two presidents to nelson mandela's funeral. captured only through a white house lens while the press corps was in the back of the plain. >> the white house is getting the only control. >> reporter: 30 news organizations recently joined in a letter to the white house charging the administration is blocking the public from having an independent view of the executive branch of government. last week the fight boiled over in the briefing room with press secretary jay carney insisting the president values the independent media. >> we're going on work with the press and the photographers to try to address some of their concerns. >> reporter: historically presidents have tried to control their image through official photos but social media has made

this government's pr push a lot easier. >> the availability of twitter, flicker, allows them to do it without any filter of the media. >> reporter: it is not only the press cameras being shuttered. denying the media unscripted answers that might be news worthy. >> his promises, consistent promise of a transparent administration led people to believe that the access would be different. that it would be greater. >> reporter: now a study by the university who you just saw there, found president obama answered fewer shouted questions than presidents bush or clinton but has had more one-on-one interviews. press secretary jay carney will meet with journalists to discuss it on tuesday. >> thank you. when "nbc nightly news" continues, why you may be getting more than you bargain for when you use your mobile device to hunt for the best deals. and later, how some of

santa's good job! still running in the morning? yeah. getting your vegetables every day? when i can. [ bop ] [ male announcer ] could've had a v8. two full servings of vegetables for only 50 delicious calories. see who does good work and compare costs. it doesn't usually work that way with health care. but with unitedhealthcare, i get information on quality rated doctors, treatment options and estimates for how much i'll pay.

that helps me, and my guys, make better decisions. i don't like guesses with my business, and definitely not with our health. innovations that work for you. that's health in numbers. unitedhealthcare. boom! get it! spin! oh nice hands! now this is my favorite play! oh! [ male announcer ] share what you love, with who you love. kellogg's frosted flakes. they're grrreat! the most free research reports, customizable charts, powerful screening tools, and guaranteed 1-second trades. and at the center of it all is a surprisingly low price -- just $7.95.

in fact, fidelity gives you lower trade commissions than schwab, td ameritrade, and etrade. i'm monica santiago of fidelity investments, and low fees and commissions are another reason serious investors are choosing fidelity. now get 200 free trades when you open an account. for those of you who haven't started your christmas shopping yet, there are just nine shopping days left. we have a warning for bargain hunters. the apps you use to find the best deals are also being used to find out a bit more about you. >> reporter: chicago and maureen brown is hitting the stores this holiday season. >> let's see. >> reporter: smartphone in hand. >> i have the best buy app, target, cvs, wall green's. they send you coupons and let you know what kind of deals they're offering. >> reporter: at sears it is part

social network. >> there are people who checked in and give tips. >> they give tips. they can post surveys, you can say which of these shirts is more fashionable. >> reporter: this year more shoppers than ever say they'll use smartphones to use more about stores but at the same time, stores are using our phones to learn more about us. apps like shop kick already alert 6 million users to deal when's they walk into more than 7,000 stores. like best buy, target, jcpenney. very soon if you let them, they'll foul as you shop at select macy's. >> we can send customers notifications about products they love as they're standing right near that product. >> reporter: the analysis firm retail next can follow a smartphone's wi-fi signal to follow traffic, even seeing how many people walk past the door. >> we can get those numbers and we can understand. wait a minute. what do i need to do differently to get more customers to come

into the store? >> reporter: if that feels too much like big brother, shoppers can disable their wi-fi. >> a consumer that knows exactly what they want out of an application and exactly what he or she is willing to give up in materials of privacy or other information can get a lot out of these applications. >> reporter: for maureen brown, sharing her name, e-mail address and shopping habits is part of the deal. >> we put so much information out there blindly. >> to lots of people we're part of the problem. >> reporter: for now she's willing to give up some privacy to save some money. nbc news, chicago. to save some money. nbc news, chicago. i'm beth...e back, and i'm michelle. and we own the paper cottage. it's a stationery and gifts store. anything we purchase for the paper cottage goes on our ink card. so you can manage your business expenses and access them online instantly with the game changing app from ink. we didn't get into business to spend time managing receipts,

that's why we have ink. we like being in business because we like being creative, we like interacting with people. so you have time to focus on the things you love. ink from chase. so you can. eating healthier,tion by drinking plenty of water, but still not getting relief? try dulcolax laxative tablets. dulcolax is comfort-coated for gentle, over-night relief. dulcolax. predictable over-night relief you can count on.

the sad news came from his agent, actor peter o'toole died peacefully saturday at a london hospital following a long illness. he was 81 years old. his film and stage career

spanned more than 60 years. we get more from nbc's jim maceda. >> reporter: peter o'toole began his career as a bright young star of the british stage but the world came to know him with those piercing blue eyes in "lawrence of arabia" where he played the british officer in world war i, landing o'toole an oscar nomination as best actor in 1962. >> you look great. >> nine centuries ago. >> time to be great again. >> reporter: o'toole was good again and again winning seven more oscar nominations including for his 1960s roles. goodbye mr. chips. >> you all hated me for this but i am very particular. >> reporter: he held a dubious record. the most oscar nominations without ever winning one until an honorary award in 2003.

>> he did point out that he was the son of a book maker, the guy who bet on race horses. and i think he sort of appreciated the irony in his own lifetime, peter o'toole was never a sure thing. >> reporter: he was known for his krousing and heavy drinking. he gave up drinking after a bout of pancreatitis almost killed him. tonight film and theatergoers in london's west end were saddened by the news. >> it is a sad loss in the film industry and as an actor. he was so renowned and well respected. >> reporter: two years ago he was honored by hollywood. peter o'toole, rakish, sue people areally talented, one of the best actors of his generation. still ahead, the holiday as generation. sshe's always been abley as to brighten your day. it's just her way. but your erectile dysfunction - that could be a question of blood flow.

cialis tadalafil for daily use helps you be ready anytime the moment's right. you can be more confident in your ability to be ready. and the same cialis is the only daily ed tablet approved to treat ed and symptoms of bph, like needing to go frequently or urgently. tell your doctor about all your medical conditions and medications, and ask if your heart is healthy enough for sexual activity. do not take cialis if you take nitrates for chest pain, as this may cause an unsafe drop in blood pressure. do not drink alcohol in excess with cialis. side effects may include headache, upset stomach, delayed backache or muscle ache. to avoid long-term injury, seek immediate medical help for an erection lasting more than four hours. if you have any sudden decrease or loss in hearing or vision, or if you have any allergic reactions such as rash, hives, swelling of the lips, tongue or throat, or difficulty breathing or swallowing, stop taking cialis and get medical help right away. ask your doctor about cialis for daily use and a 30-tablet free trial. boom! get it! spin! oh nice hands! now this is my favorite play!

oh! [ male announcer ] share what you love, with who you love. kellogg's frosted flakes. they're grrreat! still running in the morning? yeah. getting your vegetables every day? when i can. [ bop ] [ male announcer ] could've had a v8. two full servings of vegetables for only 50 delicious calories. two full servings of vegetables this is a map of the pressure points on my feet. i have flat feet. i learned where the stress was at the dr.scholl's foot mapping center. then i got my number, which matched the custom fit orthotic inserts with the right support. find your closest foot mapping center at drscholls.com. i'm a believer. they don't know it yet, but they're gonna fall in love, get married, have a couple of kids, [ children laughing ] move to the country, and live a long, happy life together where they almost never fight about money. [ dog barks ] because right after they get married, they'll find some financial folks who will talk to them about preparing early for retirement and be able to focus on other things, like each other,

which isn't rocket science. it's just common sense. from td ameritrade. finally tonight, some of the of some of santa's helpers have been busy decking the halls to make sure they are brighter than they otherwise might be for some struggling military families. janet shamlian has this festive house call. >> reporter: on a brisk colorado morning, an early christmas at the home of airman matt anderson and his family. >> we're going to do a great christmas to make your life more enjoyable.

>> reporter: despite pleas from their two sons, they had given up on the idea of decorating their home. the 5-year-old has been fighting for his life after a leukemia diagnosis changed his life six months ago. >> your chest just drops. you're thinking, no! it is just pneumonia or something. they're wrong. >> reporter: the starting news prompted him to stay home facing battle zone deployment and trips in and out of the hospital for chemotherapy on. this day for this family, christmas cheer arrived. >> what a great way for us to do something to give back. to say thanks. >> christmas decor started decorating soldiers' homes. they are among 100 getting the full decked out treatment this season. for the military families it is always a surprise. especially for the children, it is like christmas came early. for nate and older brother ben,

it was as if santa himself stopped by and maybe he had. >> it was amazing just to see. a crew of 10, 15 guys super excited. they're all here for us. >> reporter: even with his home transformed into something out of the north pole, he never lost sight of what this was really all about. >> what is the best part about the holidays? >> the best part about the holidays is family. >> it sure is. >> having a break from school and getting to ride my bike around. >> 3, 2, 1 -- merry christmas! >> reporter: thanking those who served by brightening their holiday. janet shamlian, nbc news, aurora, colorado. that's "nbc nightly news" for this sunday. stay tuned for football night in america followed by the cincinnati bengals versus the pittsburgh steelers. brian williams will be here tomorrow. i'm lester holt reporting from new york. we'll leave with you a special holiday concert featuring scores

of tuba players right outside our rockefeller studio.