on the broadcast tonight, warning signs. stunning news about autism in america and the soaring number of children being diagnosed. the heroic effort on the mountain as the tragedy grows. an incredible story of survival, the children who made it out alive. undercover bust at one of the busiest airports in america. what all travellers worry about, who is rifling through your luggage. papal visit. the president and pope together at the vatican. and the amazing friendship. a little girl, her big hero, and how their story is inspiring so many people. "nightly news" begins now.

good evening. brian is on assignment tonight. i'm lester holt. new government findings are tonight providing a stunning and eye-opening look at the growing number of families living with autism. based on the latest survey data, the centers for disease control estimates 1 in 68 american children has been identified with an autism spectrum disorder. that's about 30% higher than previous surveys. autism spectrum encompasses a broad range of developmental disorders, affecting among other things speech and social interaction. this brings new urgency to finding the cause of autism and understanding why it seems to be on the increase. our chief medical editor dr. nancy snyderman has more. >> reporter: 6-year-old ava cristos starts her day at the academy, a new jersey school for children with autism. today, a surprising cdc survey

of 11 states finds there is a dramatic jump in the number of children like ava. the cdc finds that the numbers are steadily rising over the last decade to 1 in 6 children. boys are five times more likely than girls to have autism, 1 in 42 boys versus 1 in 189 girls. what may be the most troubling facts, nobody knows what is behind the increase. experts believe that some of the numbers may be due to better detection of numbers that could have been previously overlooked. >> physicians, health care providers, educators, are clearly getting better at identifying autism as well as the case definition, you know, what is autism, is really evolving. >> reporter: the news comes as no surprise to kim cristo, whose daughter, ava, was diagnosed at with autism at 18 months. >> no parent wants to hear that their child has autism because

nobody wants to hear the a-word, but you have to fight. it is so important as soon as you hear that, for your child. >> reporter: experts conclude you should have early screening, most are diagnosed after age four, too late, experts say they can be diagnosed as early as age two. >> early intervention leads to a better outcome. so for us to provide access to care and coverage for that care for any child who is diagnosed with autism, we know we can make a world, a lifetime of difference in that person's life. >> reporter: for families like ava's, triumphs come in simple acts. >> the other night she wanted pizza for dinner. she said "i want pizza." wow, she told me what she wanted. that was such a milestone. >> reporter: kim christo hopes this new report leads to better awareness for families living with autism. >> people look at very negatively. and i think that we need to change the way we look at it. >> reporter: the main takeaway, parents should act early when there are some concerns.

so here are some signs to look for. by six months of age a baby should be smiling and making eye contact, by 12 months responding to their names and pointing to objects and babbling. it's so important to talk to your daughter if you see any signs of developmental delays so you can start getting the right therapy at the right time. lesser? >> all right, dr. nancy, thank you. now to the search for those missing in washington state, five days after the devastating mudslide north of seattle. nbc's joe fryer is there for us tonight. joe? >> reporter: good evening, lester. the official death toll is still 16, but that number could rise substantially in the next day or two after the medical examiner identifies more victims. meanwhile, as many as 90 people are still considered missing. at the scene of the mudslide, search teams use an excavator to slowly dig through the debris. >> in some cases we have had houses that are more intact than others. some of them look like they have been put in a blender and dropped on the ground. >> reporter: each time a victim's body is recovered, they pause to show respect.

>> it gets really quiet for a few minutes. you can almost hear a pin drop out there. you see seasoned veterans in this business, they start to tear up. >> reporter: all week we followed the story of dayn brunner, a dedicated brother trying to find his sister, summer raffo. he took video documenting the challenges as he walked through the areas of mud. >> my mom wants to hold her for the last time, i'm going to make sure it happens. >> reporter: wednesday, they found summer's body in the driver's seat of her car. dayn immediately called their mom. >> she immediately started crying and was kind of taken aback, and then she goes, go get her, dayn, go get her. bring her home to me. >> reporter: today, relatives say searchers also found this little girl who died with her grandmother, as the terrible search continues, they wake up at 5:00 a.m. each morning to feed the goats on their farm, then to return to the scene to look for their neighbors. >> i think what would be the worst thing as a parent or

grandparent or a brother or sister, knowing that my loved one has never been found. >> reporter: there are also stories of survival. luan that langton was hosting a party with several kids saturday when they saw a wall of mud rushing down the hill. >> and all of a sudden i saw a huge mud wave just come up to a house like a tidal wave and just crash it. and then i ran screaming. >> reporter: somehow the slide stopped just feet from their home. she called 911. >> there is a mudslide, the houses are gone, i got people here screaming for help! >> i was thinking, well, this is the end. i'm going to die. >> reporter: in a place that might seem hopeless, there still is no shortage of faith, even for dayn brunner. his sister found, he will keep searching for others. >> this community will be reeling for a lifetime. and i will take the time to be with my family for the next day or so and then i'll be right back out there.

>> reporter: more than 200 people are taking part in the search with more help expected to help relieve those in desperate need of a break. more rain is also expected adding more challenges to what is already a difficult search. lester? >> all right. joe fryer tonight, joe, thank you very much. now to the other search we have been following, that for malaysia airlines flight 370. it has resumed again tonight off australia after being suspended for rough weather in the southern indian ocean. it is the first chance for search crews to reach the new area of debris spotted by satellite being called the best lead yet. nbc's tom costello is following developments from washington. tom? >> reporter: hi, lester. almost three week news since flight 370 went missing, and search teams still have not found a single piece of wreckage.

now, more satellite images of what could be a debris field 1600 miles from australia. the thai satellite photos were taken on monday, images of what they say could be debris in the ocean, and in the same general area that a french satellite spotted debris a day earlier. also today, japan released this map showing the area its satellite photographed what could be ten pieces of debris, the largest piece measuring 13 feet by 26 feet. but the weather in the area has been awful, high winds and waves and icing conditions forcing search aircraft to turn around. pilot says the whitecaps on the water and poor visibility make it nearly impossible to identify anything. >> we're flying so quick. we're flying at 200 knots going as slow as we can go for this mission that you really get very little time to identify objects. >> reporter: now with only nine days of battery life left on the black boxes, search teams are racing against the clock and mother nature with more bad weather a possibility on friday and sunday. lester? >> all right, tom costello in washington, thank you. for month, new jersey

governor chris christie has been trying to control the damage over the role his administration played in closing lanes leading to the george washington bridge causing massive traffic jams. today the results of an investigation commissioned by chris christie's own office were released. we get more tonight from nbc's kelly o'donnell. >> reporter: today outside lawyers hired by the office of new jersey's governor and paid for by taxpayers cleared chris christie. >> what we found was that governor christie had no involvement in the decision to close these lanes and no prior knowledge of it. not a shred of evidence of it. >> reporter: the 360-page report follows a ten-week review of the bridge traffic lane scandal that threatened christie's political future. the governor turned over his personal and work e-mails and texts and was interviewed several times. last night, christie was on new jersey radio. >> i think all the important questions will be answered. >> reporter: the review puts all the blame for the plot to snarl traffic in fort lee on former port authority official david wildstein.

and the governor's now fired top aide bridget anne kelly. both wildstein and kelly have taken the fifth and did not cooperate. the report shows a new allegation, claiming that kelly lied to her bosses and after the deleted e-mails, kelly responded good, after the fort lee mayor complained about the mess. >> you ask me what i take from that? i take somebody who did wrong is trying to cover it up from the chief of staff and the governor. >> reporter: taking on another issue, the review dismissed claims made by hoboken mayor dawn zimmer that christie's administration had threatened to deny sandy relief money unless the mayor backed a commercial development. today mayor zimmer responded calling the review sadly predictable and a one-sided whitewash. today's findings will eventually be judged against conclusions reached by other investigations still under way. kelly o'donnell, nbc news, washington.

overseas today, a historic meeting at the vatican between pope francis and president obama. the two men talked for just under an hour, discussing a wide range of topics. our chief white house correspondent chuck todd is traveling with the president in rome. >> reporter: president obama said his audience with pope francis featured a wide-ranging discussion, from middle east peace to immigration reform to their shared interest in eliminating income inequality. >> his holiness has the capacity to open people's eyes and make sure they're seeing that this is an issue. >> reporter: the president arrived at the vatican this morning amid pomp and pageantry, welcomed by swiss guards, a slow procession of dignitaries escorted mr. obama to the pope's study, where the two sat face-to-face across his unassuming desk. joined by translators, they eventually retreated behind closed doors for nearly an hour.

it was longer than scheduled and afterward they exchanged gifts. the president gave the pope a custom-made chest, featuring a variety of fruit and vegetable seeds used in the white house garden. and the pope presented mr. obama with two medallions symbolizie ing peace and a copy of "the joy of gospel." the white house viewed this trip as a big domestic political play of the trip, a chance to associate the popular pope francis with the president's own economic agenda. the president said he and the pope didn't talk a lot about the social issues that divide them like contraception and gay marriage, but in a later meeting with vatican officials, he did discuss the church's concern over the affordable care act contraception mandate. >> we discussed briefly the issue of making sure that conscience and religious freedom was observed in the context of applying the law. >> reporter: the president also made time today for a private tour of the roman coliseum, where the gladiators once did battle.

>> i got to check on one of the seats. it's remarkable. unbelievable. >> reporter: traveling with the president, chuck todd, nbc news, rome. still ahead as we continue here tonight, the sting. a massive bust at one of the busiest airports in the country. the fears of so many travellers, what happens to your luggage when you can't see it. and later, honoring the fallen. an emotional scene today in boston. brian williams will join us from there just ahead.

we're back with a wake-up call for anyone who flies about what can happen when you check your bags. we're not talking about just losing your luggage, we're talking about people stealing from your luggage, people who work at the airport. in los angeles tonight, half a dozen current and former airport workers are accused of doing just that. we get more tonight from nbc's gabe gutierrez. >> reporter: it was a surprise sting operation at one of the world's busiest airports, people trusted with handling your

luggage led out in handcuffs, one still wearing his security vest. >> this is the first time we have engaged in a very, very long-term extensive operation to try to identify as many people as we can. >> reporter: 14 current and former airport workers detained, six were arrested. they had been contracted by the airport to handle baggage. security says they handled jewelry and other items before they luggage even got to the baggage claim. >> anybody who works at the airport has to pass a security background, which includes, you know, criminal history checks. >> reporter: undercover officers began their investigation months ago after a string of reported theft from terminals, runways and planes. l.a.x. handles nearly 55 million piece of luggage a year. and while police say the reported thefts represents a small portion of, that it's a concern for many travelers. >> i had some shoes stolen from me and other small items. >> reporter: over the past few years, we've seen thefts caught on camera at airports around the country, from new york to atlanta to chicago to denver,

all of it leaving passengers wondering how safe their bags really are. >> you are hoping things are safe. you depend on it. it is very scary. >> reporter: emily peterson arriving in los angeles today from boston doesn't take any chances with checked baggage. >> i assume that people are going through my luggage anyway, so i always take precautions. i keep valuables, my jewelry on me, on my carry-on. >> reporter: tonight, police are trying to return the stolen items to their owners, what they may never get back is their peace of mind while traveling, gabe gutierrez, nbc news, los angeles. up next here tonight, we'll check in with brian williams. he'll be joining us live from boston as firefighters gather to honor their own.

a heart-wrenching scene in

boston. a sea of firefighters lining the streets to salute the fallen after a ferocious fire consumed a row house in the back bay area. they're grieving the loss of 43-year-old lieutenant edward walsh jr., a veteran firefighter who leaves behind a wife and three children under the age of 10. and 43-year-old firefighter michael kennedy, a veteran firefighter, one of the first responders at the marathon bombing. and as we approach that day, brian williams is on scene from boston and joins us from the scene of so much sadness, on lad err 15 on boylston street. we're here after the scene. >> reporter: what a sad day in boston. they just don't lose professional firefighters in the line of duty that often, say nothing of two of their bravest from the same house, one of the oldest in the nation.

you wouldn't blame anybody in the city for asking how much one city is expected to take in the course of a year. if there is a blessing it is this community. it is tight, let's face it, it is a heavily irish occupation in a heavily irish city. they have lost two irishmen, and last night, pubs from bars from south boston and all over raised a glass to the memories of the families. you can't blame anyone here for just waiting for the next patriots day in a few weeks so they can have a proper finish not far from here down boylston for the boston marathon. lester? >> all right, brian, thanks. we'll see you back here tomorrow. we learned today that james schlesinger has died. he served under nixon and ford, he was known for taking a hard line with congress on the defense budget. nixon also made him cia director. as the country's first energy secretary under jimmy carter, schlesinger was a strong advocate of nuclear power. james schlesinger was 85 years old. the kennedy library

foundation announced today it will present its 2014 jfk profile in courage award to former president george h.w. bush for his 1990 decision to raise taxes as part of a budget deal with congress. during the campaign, bush had famously said "read my lips. no new taxes." his decision to break that promise not only took courage, as the award says, it also may have cost him reelection. former president bush turns 90 this june. and when we come back here, team spirit. a star player's biggest fan and the feeling we can tell you is mutual.

finally tonight, when michigan state battles virginia tomorrow night in basketball's sweet 16, an 8-year-old girl will be among the biggest fans, rooting especially hard for michigan state's 6'10" center. turns out he is a big fan of hers, too. nbc's stephanie gosk caught a beautiful friendship. >> reporter: in the middle of march madness it is no surprise michigan state adrian payne has basketball on the brain. what's surprising is tomorrow night's game isn't all he is

thinking about. the 6'10" center has been texting and checking in on 8-year-old lacy hallsworth all day. >> he just texted her to ask how she was doing. >> reporter: payne met lacey two years ago when the team was visiting sick children in the michigan hospital. >> she loved to dance. and then all of the sudden, boom, this happened. >> reporter: the towering center connected with the little girl battling cancer. >> she just found something about him that was really special. >> i lost my mom and grandmother. i don't know how it is losing a child or having to go through something like that. >> reporter: the two really like to color together. >> that is how i color, when i'm with you. >> reporter: looks like you have become a much better colorer. >> yeah, yeah. i did. >> reporter: earlier this month, michigan state won the big 10. lacey was there, cheering him on and sharing in a time-honored tradition. >> that was really fun. i got to climb up there and help

him cut down the net. >> reporter: but last fall, it was lacey who needed the support. >> lacey kind of relapsed and she had -- was having a real rough week. >> reporter: until adrian got there. >> she turned over and she seen me, and she grinned. she made a little smile. >> reporter: coach tom izzo was there that day too. >> watching that moment, i could never teach that. i could never coach that. >> reporter: a 23-year-old on the cusp of making the nba, showing the kind of selflessness that would be admiral in anyone at any age. >> she called me her superman. >> superman, i love you. >> reporter: a win for both of them. no matter what happens on the court. stephanie gosk, nbc news, new york. that's our broadcast for this thursday night. i'm lester holt. brian will be back tomorrow. thanks for being with us. good night.

nbc bay air what news starts now. he will not be on the floor of the senate ever again. >> a tough message tonight to the state senator charged with serious federal crimes. leland yee has not resigned. >> senator yee's not only facing more than 100 years in prison but also facing his colleagues and constituents, many of whom want him out.

tonight, some key defissions about yee's uncertain future. this comes after the fbi arrested him yesterday for corruption and dealing firearms. we begin live from the federal courthouse. chase? >> reporter: i talked to the secretary of state's office late this afternoon. and they say despite the fact that leelaland yee has withdraw from the race, it's too late to remove his name from the ballot. he says there are no plans for the state senator to resign. so that should set in motion a plan by democrats to vote to suspend yee from office. >> every indictment, every arraignment, every arrest reflects very poorly on a proud institution. >> reporter: state senator mark leno did n