ions are still exposed to the dangers... of secondhand smoke... and some of them can't do anything about it. ♪ [ continues ] [ gasping ] on our broadcast tonight, out of the race. rick santorum has ended his come from behind campaign for president. and what now for the gop? the bizarre twist in the trayvon martin death investigation. george zimmerman's own lawyers can't find him. x-ray risk. news tonight that dental x-rays can raise the risk of brain tumors, and what you should do the next time you visit the dentist. red flags up and down the east coast. more than 20 states on high alert for wildfires. exactly the kind of thing we're used to seeing out west. and the titanic. 100 years since the unsinkable ship went down. tonight, a century old legend lives on. "nightly news" begins now.

captions paid for by nbc-universal television good evening. the start of the 2012 general election season might some day be traced right back to today. this afternoon in gettysburg, pennsylvania, not far from the very heart of the civil war battleground, rick santorum got out of the gop race. the battleground that went on longer, was more brutal and divisive than anyone had first imagined. he won 11 out of 50 states. but it's another number that was trouble for the former pennsylvania senator, 1,144, the number of delegates the nominee will need. and it's mitt romney who is much closer to that. we begin our coverage tonight with nbc's ron mott on the trail in gettysburg. hey, ron, good evening. >> hey, brian, good evening to you.

after waiving off repeated questions over the past couple weeks over whether he should get out of this race, today rick santorum made it official, leaving, yet leaving open the possibility he's far from done on the political stage. his momentum fading. one day after his ailing 3-year-old daughter bella returned home from the easter weekend spent in the hospital, rick santorum bowed out. >> well, this presidential race for us is over, for me. and while we will suspend our campaign effective today, we are not done fighting. >> reporter: santorum pitted his grassroots, every man bowling alley, blue collar roots against mitt romney's polished, upper crust image, with unexpected success. >> against all odds, we won 11 states. millions of voters. millions of votes. we won more counties than all the other people in this race combined. >> reporter: his exit, with no mention of romney by name, spares the ex-pennsylvania senator the prospect of another embarrassing defeat in his home

state, having lost his u.s. senate seat six years ago 37. santorum's support was mostly rooted in a core of republican strong holds, where his unapologetic push for conservative strongholds was enthusiastically embraced by evangelicals. but in general election battlegrounds like ohio, wisconsin and michigan, he could not top governor romney. it was a campaign filled with highly publicized gaffes. >> what a snob? >> reporter: from calling president obama out on education, to president kennedy's famed speech on the separation of church and state. >> you bet that makes you throwup. >> reporter: just two of a snub of comments he eventually walked back or was pushed to explain. >> you know, we get a little fired up sometimes, and say some things, i wish i had a mull mulligan on. >> reporter: going forward, many republicans fear the relentless pounding of romney by santorum could affect his chances in the polls, with barbs like this. >> he is the worst republican in the country to put up against

barack obama. >> reporter: what's next for rick santorum? no word just yet. his campaign did today send out an appeal for money, and confirmed that mitt romney has asked for a meeting. something rick santorum says he's open to. no details on when that might take place. >> all right. ron mott starting us off tonight from gettysburg, tonight. ron, thanks. with that, we go to the moderator of "meet the press" david gregory. david, i know you've been on the phone this afternoon to one of the few remaining candidates still technically in this race. >> well, right, we're down to a few now. newt gingrich is still the prominent one there. he's still in the race. i spoke to him this afternoon, he's going to stay in it. at this point, primarily to define the party platform, the issues going-forward. bottom line is, he thinks he can have influence, he still thinks there are questions about whether romney is a trusted conservative. but this general election contest is moving on without him. even if he stays in the race, there was a conversation between romney and santorum today. romney wants his support, the

endorsement. the santorum team saying they're going to need a couple days before they get all that together. romney is not wasting any time, speaking out and speaking very positively about the campaign that santorum ran. he spoke in delaware this afternoon. >> he has brought forward issues he cares very deeply about. he has been able to gather a great deal of public support and interest in those issues and in himself. he will continue to have a major role in the republican party. and i look forward to his work in helping assure victories for republicans across the country in november. >> still a big future for santorum, probably a big convention roll, brian. and you have to imagine the prospect of losing his home state of pennsylvania certainly weighed heavily on the santorum campaign. that's what they were saying there toward the end. >> absolutely. david gregory in our d.c. newsroom. david, thanks, as always. now, to sanford, florida where today george zimmerman's lawyers called a press conference to say, they have no idea where their client is, so they're withdrawing as his lawyer. then we later learned they were

never really in touch with him face-to-face in the first place. the strange case of the death of trayvon martin got stranger today. our coverage begins with nbc's kerry sanders. >> reporter: george zimmerman's legal team walked to the podium and then announced they're no longer his lawyers. >> at this point we're withdrawing as counsel. if he wants us to come back as counsel, he will contact us. >> reporter: two attorneys say they had never met their client, george zimmerman, but they had an open line of communication with him, via e-mail, text and phone. but on sunday, the two say there was inexplicable silence. and it's been like that since. and contrary to their advice, they say zimmerman reached out to the special prosecutor, angela corey. >> one of the things every defense attorney tells his client is, don't talk to the prosecutors, don't talk to the cops. frankly, don't talk to anybody. >> reporter: the day they lost contact with zimmerman, sunday, is the same day the internet registry shows george zimmerman set up this web site.

while his lawyers say they thought he was exercising his right to remain silent, he found a way to speak out. on his welcome page, zimmerman writes in part, "i was involved in a life altering event, which led me to become a subject of media coverage. i've been forced to leave my home, my school, my employer, my family, and ultimately my entire life." and there is a link to donate, funds he says that are only for living expenses and legal defense. >> our concern is that for him to do this when he has a couple professionals out there working as hard as we were for his benefit, to handle it this way suggests that he may not be in complete control of what's going on. we're concerned for his emotional and physical safety. >> reporter: trayvon martin's family -- >> it takes a lot of patience dealing with this. >> reporter: and their lawyers tell nbc news they're stunned and fear george zimmerman could be a flight risk, if the special prosecutor chooses to bring charges. >> will he ever be brought to

justice, if and when he is charged for killing their son? those are some very serious questions. >> reporter: as for george zimmerman's whereabouts, his former lawyers say they believe he's in hiding and no longer in the state of florida. they say they continued to believe in him and stand at the ready, because if they want representation, they say they're ready to represent him, again. brian? >> kerry sanders, thanks. and our chief legal correspondent savannah guthrie joins us here in the studio. we've all seen too many cop shows. we've seen those scenes where they're told to stay close, don't make any travel plans. you're a lawyer, how common is it to lose your client? >> this is not common. there's nothing ordinary about what we saw happen today. these lawyers couldn't get their client on the phone, but the state prosecutor could? it's incredibly odd. it was odd, frankly, that the lawyers came out and gave this public press conference announcing they would no longer represent george zimmerman, when

a simple paper statement would have sufficed. instead, we learned he's not living in florida, he's doing things that are quite unorthodoxed, suggesting his mental state may be at issue. and you wonder if the end result may be, as a prosecutor who's looking at this and saying, wait a minute, should i bring charges more quickly because he may be a flight risk or a danger to himself? it was a very, very odd development today. >> thank you, savannah, for being with us. now we turn to a clear and present danger. in 20 different states along the eastern seaboard that we normally associate with the american west, wildfire and brushfire warnings. it's the price you pay for a winter season that never really did show up in a lot of places, saying nothing of the usual snowfall. now it falls to firefighters to slog it out. our report from nbc's tom costello. >> reporter: it may only be the second full week of april, but fire season has arrived weeks if not months ahead of time. on long island new york, three firefighters were injured as they battled a wildfire that

consumed 1,000 acres, destroying nine commercial buildings and three homes. >> it's heartbreaking. you live in a house for 25 years and you have all your personal possessions in there. >> reporter: near milford, connecticut, a stubborn fire along the tracks forced amtrak to suspend service for hours. while in southern new jersey roughly 1,000 acres blackened in burlington county. up and down the east coast, firefighters have been battling heavy smoke and flames for more than ten days now. weather channel meteorologist mike seidel. >> everything you see in red here indicates the warmest start of any year on record. plus, many northeastern states have had their top ten driest starts on record. those two factors and the recent wind is the perfect recipe for fire. >> reporter: already, 24 states and d.c. have posted red flag fire warnings, extremely unusual on the east coast. with fires as far north as massachusetts. in atlanta today, traffic on i-285 south had to crawl through dense smoke.

while in florida, jacksonville issued an air pollution alert with dozens of fires burning statewide. >> once it got a good seat, it began to run in that area. it had a lot of fuel with it. and given the wind speed conditions we've seen, that type of fire is not unusual. >> reporter: compounding the problem, humidity levels remain unusually low. >> we haven't seen any rainstorms or snowstorms, and all the vegetation that grew up rapidly from last winter's rainfall is dry and ready to burn. >> reporter: an early start to a season, and already busy on the fire line. fire commanders say it is so dry, so windy, and there's so much dry fuel out there, it only takes a cigarette or a downed power line to get a fire that's going and out of control. they're asking everyone in the affected states to use extreme caution. brian? >> all right. tom costello just outside washington, d.c. tom, thanks. on wall street today, fresh worries over debt in europe made for a turbulent day. sent stocks sharply lower, the dow was down more than 213 points.

nasdaq lost almost 56. s&p 500 down over 23 points. all three are now down for five trading days in a row. with the dow and s&p 500 now off 4% in those five trading sessions. now to our exclusive reporting from inside north korea, where today the secretive regime opened the door a bit for visiting journalists, while insisting it would go ahead with a controversial satellite launch as early as this week, despite all the international condemnation. our chief foreign correspondent richard engel reports again tonight from pyongyang. >> reporter: north korea says its rocket is ready for the launch. the satellite loaded. at a press conference pyongyang, a defiant announcement. north korea says it's designing even bigger rockets, and better satellites. and there was more they wanted journalists to see. earlier we were bussed through the capital, along streets now lined with flags. we were taken to see a state run

breeding house for turtles. here, this 36-year-old cleans and feeds the breeding pools with a reminder ever present. he says he supports the satellite and rocket launch. he also helped satisfy a curiosity i had, about the mass rallies like the one i saw in pyongyang yesterday. how do you know when you're supposed to hold up the decorations and when you're supposed to applaud? do you receive some training in this? >> translator: we have a conductor. if you want to learn -- >> you'll teach me? >> okay. >> reporter: finally, we visited a sparkling clean factory making apple juice. but the machines seemed to produce remarkably little. was the tour a show? certainly. but it's revealing how north korea wants to see itself, modern, strong, independent. this is one of the largest and most advanced factories in all

north korea. and if there's any doubt to whom it's dedicated, there shouldn't be. kim jong-il's ubiquitous portrait smiles down on the north korea officials here want the world to see. richard engel, nbc news, pyongyang. still ahead as we continue along the way tonight, today's health news story about a possible link between dental x-rays and brain tumors. and later, they call themselves the three amigos, and they just got their share of the giant jackpot. but who are they?

the health news story today got everybody's attention, mostly because of how big dental x-rays have become in the past

few years. they're almost impossible to escape. and because of new research just out raising questions about a possible link to brain tumors. our report from our chief science correspondent robert bazell. >> reporter: at this dental clinic today, dentists say they have long been telling patients, that x-rays should be taken only when absolutely necessary, especially for children. >> we use it very sparingly. we don't usually take x-rays on children under 6 years old, unless there's an indication. >> reporter: a study out today gives more reason for concern, finding frequent or yearly dental x-rays might double the risk for a common, usually nonmalignant brain tumor, called a meningioma. 5,000 are diagnosed in the u.s. yearly, three times as many in women as men. the research is prompting plenty of questions. >> why would i want to constantly every year get an x-ray? >> i'm not entirely confused. >> don't panic, don't stop going to the dentist, and have a conversation with your dentist

about whether you might be able to reduce the number of dental x-rays. >> reporter: researchers compared almost 3,000 people, average age 57, with and without meningioma and asked them how many dental x-rays they had, including in childhood. since there are few records, people's memories of such studies can be unreliable. the study at best suggests a connection. >> we cannot say from this article that x-rays cause the brain tumors. >> reporter: in addition, x-ray technology has changed. a typical dental x-ray today exposes patients to hundreds of times less radiation than it did decades ago. since meningioma takes 20 to 30 years to develop, most people in the study were exposed long ago. >> you're brushing every day? >> reporter: the message for patients, for many experts, including the american dental association, is that dental x-rays should be used only when necessary, and in the smallest doses possible.

robert bazell, nbc news, new york. when we come back, a baby boom on the west coast, in one place in particular, and a pretty good idea why it's happening.

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deposit checks from your smartphone with chase quickdeposit. just snap a picture, hit send and done. take a step forward and chase what matters. there are still a couple of things you can't say these days, or if you choose to, be ready. if you're the manager of the miami marlins and your stadium is located in the little havana neighborhood, you can't stick up for fidel castro. you can't say as, the marlins manager, ozzie guillen did, that you love and respect fidel castro. the marlins have suspended him for five games. he apologized at a news conference today, speaking mostly in spanish, and said he was "very guilty, very sad and very embarrassed." the second of three winning tickets in that giant $656 million mega millions lottery has been claimed in maryland. like the winners in kansas, the three co-workers sharing this chunk of the prize want to remain anonymous. all we know is, the three

amigos, as they call themselves, are public school educators, two teachers and an administrator. despite the $35 million windfall coming to each of them, the good news for the kids is, they all say they will keep their day jobs. you may remember carmageddon in l.a. last year, the road was closed everyone was told to stay home, stay off the roads. they did. here's how we know. cedars-sinai hospital is reporting a huge influx of expectant moms in its prenatal classes. that would put it right about the 40 week mark, and that seems right. jack tramiel has died. he was a holocaust survivor from auschwitz. he came to this country, started a typewriter repair business. and then changed everything when he invented the commodore 4 back in 1977. which, of course, opened the personal computer era. he went on to buy atari. he often lectured in schools about his experience in the camps long ago.

jack tramiel was 83 years old. up next here tonight, why there's never been anything in the world's imagination quite like the most famous voyage of them all.

it still sells movie tickets, it has a hold on our

imagination, what must it have been like on board the titanic on that awful night in the north atlantic? today they commemorated the 100th anniversary of the ship's departure. our report from nbc's stephanie gosk in southampton, england. >> reporter: in southampton, england they commemorated the day the world's most famous cruise liner set sail for the first and last time. >> that was the picture in the newspaper. >> reporter: barbara cohen's great uncle was on board. >> i just find the whole experience very moving and very touching. >> reporter: it was the ship they dared to call unsinkable. aboard were with some of the richest and most famous people of their time. more than 1,500 died in the icy north atlantic. a tragedy, a huge news story, and an obsession still going strong a century later. >> i'm the king of the world! >> reporter: "titanic," the blockbuster movie is back in theaters in 3d.

director james cameron has even explored the wreck and produced a national geographic special, just one of many now crowding the airwaves. titanic artifacts from the ocean floor are being auctioned off for the first time. jewelry, a chandelier, third class dish ware, expected to bring in millions. there's even a cruise that set out this week to retrace the titanic's route. >> we wanted to honor and respect the people who were on the titanic before us. >> reporter: for those who couldn't get a ticket, there's always a trip to the port the titanic made famous. one of the reasons tourists come here to southampton is to put themselves in the shoes of the passengers. to imagine what it must have been like to get on the world's biggest, most luxurious cruise liner. a ship that in just a few days, would be at the bottom of the ocean. it was a moment in history when both human ingenuity and

fallibility was on full display. and it has captured the world's imagination for a century. in the end, the titanic may have proven unsinkable after all. stephanie gosk, nbc news, south hampton, england. that's our broadcast on a tuesday night. thank you for being here with us. i'm brian williams, and we hope to see you right back here tomorrow evening. good night. good evening, everyone. thanks for squoing us. i'm janelle wang in for jessica aguirre. >> and i'm raj mathai. it is cold, it is windy, and it might get even worse. we begin with our storm coverage tonight, how it's impacting traffic at this hour, and how it will impact the rest of our week. let's bring in our meteorologist rob