autism. stunning news tonight about the number of children diagnosed, especially little boys. apple investigation. a big admission tonight about the working conditions for the people who make your iphones and ipads. first look, on tape of the man who shot trayvon martin. tonight, the question, what does it really show? pumped up. gas prices sky high, and it looks like it could be a very expensive summer. and gold rush. going west again to strike it rich. "nightly news" begins now.

good evening. i'm lester holt, in tonight for brian williams. the mere mention of the word strikes deep anxiety for parents everywhere. autism. a set of development disabilities that often send healthy outgoing children into a nearly impenetrable world of their own. and we learned that more and more american children are now considered to be autistic. the numbers are jaw dropping. according to the cdc, 1 in 88 children has been identified as having an autism spectrum disorder. among boys, 1 in 54. to put those numbers in perspective, just three years ago, 1 in 110 children were diagnosed with autism disorders. but the question many are asking tonight, are more children being stricken with the condition, or are doctors simply diagnosing them more often? nbc's chief science correspondent robert bazell has details. ♪ good morning academy how are you ♪ >> 3-year-old aiden meyers was diagnosed with autism last

summer. >> i tried to prepare myself for it. i told myself i was going to be okay with it. and today -- it was a hard day. >> aiden is among the children, 1 in 54 are boys. now diagnosed with some disorder that falls in what is called the autism spectrum. that's a 23% increase from the last survey taken two years earlier, according to the cdc. >> since 20002, the prevalence has increased 78%. >> no one is sure what is behind the numbers, but many experts believe part of it is a greater awareness among the medical establishment and among parents. and many experts say that problems that used to be labeled disorders, ranging from mental retardation to learning disabilities are now diagnosed as autism. >> the way we diagnose autism

spectrum disorders has changed. we're more inclusive. we include people with more cognitive abilities and less severe problems than we have in the past. >> what have you got in your pocket? >> sticks. >> sticks? >> no one doubts aiden meyers' diagnosis, but he's not the case of the socially withdrawn, nonverbal child. he attends reed academy in oakland, new jersey, where each child is taught full-time by a teacher. >> my little boy is riding a bike all by himself. >> many argue no matter what the reasons for the increase in cases -- >> you did it. >> -- huge numbers of children could benefit from such extra care. robert bazell, nbc news, new york. joining us now, dr. levine, a pediatrician based here in new york, she worked with the american academy of pediatrics and is a mother herself. thanks for being here this evening. this is difficult for parents to accept because there's almost a

helpless feeling that it brings about. what should parents be looking for in their children in the early developmental years. >> early intervention really improved out. if you have a child that is 18 months old and doesn't make good eye contact and doesn't recognize their own name and respond to their own name, doesn't point to things, doesn't wave, doesn't interact with other children, then you want to talk to your pediatrician. all pediatricians are screening children for autism at the age of 18 months and two years, but as a parents, you can play a role in helping with the diagnosis. >> what is the big take away? what one thing stood out in your mind we should all take away from it? >> the big take away is there's an increase in identification of children with autism spectrum disorders. this can help guide our research dollars. we need to allocate them towards finding out what is causing the autism spectrum disorders, and how we can help the children and it can also help communities to allocate resources to make sure they're available for children who need them. >> thank you for enlightening us. in other news, the first video of the florida

neighborhood watch volunteer, george zimmerman, is coming under sharp public scrutiny tonight over whether it supports his version of the fatal confrontation with teenager trayvon martin. the police video was reported shortly after zimmerman shot and killed the unarmed 17-year-old. nbc's ron allen reports from sanford, florida. >> some 40 minutes after george zimmerman claimed he killed trayvon martin in self defense, surveillance video shows police bringing him in for questioning. after what zimmerman's attorney has called a life and death struggle with the unarmed teen that left zimmerman beaten and bloodied. those demanding an arrest insist the tape refutes zimmerman's claims. >> everybody can see with their eyes in this video that evidence isn't there to support a self-defense claim. >> it's a very grainy video. i do however, if you watch, you'll see one of the officers as he's walking in, looking at something on the back of his head. >> jim is a former washington, d.c. homicide detective and

paramedic who consults in criminal cases. >> we don't want to rush into a judgment on either side. and yeah, i mean, just because you don't see something in this very poor video doesn't mean that it's not there. we have other ways of verifying these facts. besides just the video right there. >> the police report said zimmerman was bleeding from the nose and the back of the head and received first aid in the police car, and zimmerman's faurtd told a florida fox tv station, his son told him there was a scuffle on the ground. >> george was trying to get his head off the concrete. in doing so, his firearm was shown. trayvon martin said something to the effect of, "you're going to die now" or "you're going to die tonight." >> today, the funeral director who prepared martin's body for burial gave this assessment. >> i saw the evidence of the gunshot wound in the upper chest.

i did not see any signs like he had been in a scuffle or fist fight. >> justice be served. >> sheryl brown lives about 30 yards from where martin was killed. her son called 911. brown says the lead investigator told her he wanted to arrest zimmerman. >> i think his words were, we do not believe it was self defense, and that they needed to prove it. >> now the six minutes of video are fueling the growing debate about what happened. we should point out that sanford police only released the tapes because of a freedom of information quest by nbc news and other journalists. the special prosecutor in charge of the investigation said she's use florida law to block the release of any more tapes or videos to protect the integrity of the investigation. >> ron allen, thanks. >> there's breaking news about what working life is really like for thousands of workers in china making the millions of ipads and ipods selling like crazy here and around the world. apple is promising big changes at those factories. what will it mean?

we're joined by cnbc's john fort. this is all in response to an investigation into apple's labor practices in china. how damaging is that report and what happens now? >> well, lester, apple ceo tim cook was in china this week, and one of the places he stopped was in one of those factories in china. i wouldn't call this report damaging exactly, but there are some concerns though. primarily about working safety and how they prepare for that and also about overtime. in violation of the national standards for overtime. the workers are working way too much. but the workers themselves, 80% say the hours are fair or they want more overtime. there's a challenge in how apple approaches it. they say they're going to decrease the number of overtime hours but increase wages over the next year, plus, so the workers themselves don't take a hit. >> how does this affect consumers of apple products? >> well, i think there were a lot of consumers who were

concerned by buying apple products, were they supporting labor practices that were hurting the world overall, that were substandard even for china? what this report says not necessarily. this appears to be in line with what a lot of companies are doing over there and in some cases, better, because apple set benchmarks for how they're going to improve in the future. >> now to the increasing pain at the pump that seems to get worse by the day. aaa reports the national average for regular unleaded is now $3.92 a gallon. up 33 cents in the year. but it may already be above $4 where you live. chicago has the highest average in the country, $4.54 a gallon. nbc's tom costello joins us from a gas station in rockville, maryland, with more for us. good evening. >> hi, lester. $4.10 a gallon at the pump here. we as a nation are consuming less oil, importing less oil, producing more, so why are the gas prices higher? because the rest of the world is

very thirsty for gasoline. in suburban maryland this afternoon, soccer mom and kid chauffeur paula was making the daily rounds. >> now to the sports store to get birthday presents. >> but with gas hovering near the $4 mark, the daily run isn't cheap. >> i end up sort of picking a number and saying, okay, $50 is all i'm doing and lets hope it last me longer than it did the last time. >> from the east coast to the west, the same complaint, but on capitol hill today, industry analysts say the high prices may be here for a while. >> unfortunately for consumers, there's little that can be done in the near term. in a free market system, price is always the final allocatur of skaers resources. >> it's not just capitol hill talking gas pleases. the truth about oil is time magazine's newest cover story. ironically, the u.s. is consuming nearly 2 million fewer barrels of oil each day than it did five years ago, thanks in part to more fuel efficient cars, and the u.s. is producing more oil at home.

so why do gas prices keep rising? tension with iran is one reason, but the biggest factor is the exploding middle class populations in china, india, and brazil where people are buying cars and filling their tanks. for three years now, china has been the world's biggest automobile market. >> we simply are at the raw end of a tight supply chain that can only be remedied by increasing domestic natural resources. >> making matters worse, five u.s. oil refineries have or will soon shut down because of supply dhan problems. and now, more than half of all u.s. leisure travelers say higher gas prices could cut into their summer travel plans. >> i can't bear to see $80, $90 four times a month. >> as the world's demand for gas truly hits home. many analysts think we could be headed towards $4.25 a gallon as a national average, but already for a family earning $40,000 a

year, gas is consuming about $2,600 of that income. lester? >> tom, thanks. on the campaign trail, mitt romney has picked up a couple highly coveted endorsements in the last 24 hours. he flew to houston to accept the backing of former president george h.w. bush. he voiced his support for romney last fall, and last night, he picked up the backing of florida senator marco rubio who has been widely touted as a potential vp pick. still ahead as "nightly news" continues, "bully" a new film, a shocking, in-your-face look at what is happening to kids these days. they live it. should they be allowed to see it? and later, an american original. you may not know his name, but you do know his music.

there's a new film debuting that you may have heard a lot about, but it won't prepare you for the experience of seeing it. it's called "bully" and it depicts the impact of school bullying on the kids who are traumatized by it in a way we have never seen. some of the controversy surrounding this documentary has to deal with the graphic and offensive language that is part of the sorie, including some of it in our report from nbc's kate snow. >> everyone was laughing. and they knew it was hurting me, and they kept going. >> what makes "bully" so riveting, so disturbing is the access the filmmaker has. unsanitized moments in the lives of real kids. >> he called me a faggot. >> how does it make you feel? >> it breaks my heart. >> alex libby was 12 when cameras spent a year at his school in iowa, getting to know kids who faced physical and

verbal abuse. >> they punched me in the jaw, strangle me, and knock things out of my hand. >> the film opens with a father who lost his son to suicide. >> some kids had told him to go hang himself, that he's worthless. i think he got to the point where enough was enough. >> two people to a seat. [ bleep ] >> harsh language, including six f-words earned the film an r-rating. after losing an appeal for a pg-13, producers took the unusual step of releasing the film with no rating. we watched the trailer with these 13-year-olds at a middle school in bedford, new york. >> do you want to see the film? >> yes. >> there are some people who think this movie is way too tough for kids. >> is school too tough for kids? we see all that and more every day. that's just how kids act. >> the film shined a spotlight on the impact of bullying, but school psychologists say kids will need help finding solutions. >> teachers, administrators,

school board, parents, those are the ones i would love to see see the film first and then begin the conversations and begin the hard work that schools and communities have to do around bullying. >> he said some younger kids may be disturbed by the plotlines, like seeing 11-year-old trey wallace become a pall barer. when his best friend commits suicide. >> alex told us he agreed to be filmed because he thought maybe it would make the bullies stop. instead, his family moved him out of state. look at him now. >> now, i'm having the greatest time of my life, living it up. >> alex and his parents were at the l.a. premiere this week. >> the whole process has kind of brought him out of the darkness and broke him out of his shell and gave us our son back. >> i'm glad i'm actually making a difference. it's amazing. >> "bully," the movie, opens this weekend in new york and l.a. with plans to be in more cities by the end of april, but because the film is being released without a rating, it's up to individual theaters to

decide, lester, whether or not to let kids in the door to see it. >> incredibly sad. it sounds worth seeing. kate, thank you. >> we have several resources on our website tonight, including hotlines for teens who may be targets of bullies. nbcnightlynews.com. and kate snow continues her reporting on dateline on sunday with a new examination of a bullying case you may remember. dateline at sunday at 7:00, 6:00 central. up next here tonight, an incredible new number in a jackpot of a lifetime.

♪ the unmistakable sound of an american original banjo virtuoso earl scruggs has died. a north carolina farmboy who influenced generations of musicians in a career that

spanned eight decades. bringing his brand of country music to a huge mainstream audience. ♪ come and listen to my story about a man named jed ♪ >> if you have seen the "beverly hillbillies" or "bonnie and clyde," you have heard earl scruggs. in fact, anyone who plays the banjo in his in debt. he helped invent bluegrass and perfected a style of playing so distinctive, it bears his name. >> how about giving us a close-up view of scruggs style picking. >> sure, frank, the fifth string is plucked with the thumb. the rest of the strings are plucked with these two fingers. >> he got his start with the father of bluegrass, bill monroe, and then set out with bandmate lester flatt. they became country music stars. the grand ole opry, their own tv show, that "beverly hillbillies" theme.

and the "bonnie and clyde" soundtrack, bringing the scruggs sound to millions. earl scruggs became an icon, unbound by tradition, playing with all kinds of musicians and making a sound distinctly his own. a down home american classic. earl scruggs died yesterday in nashville. he was 88. the largest lottery prize in american history just keeps getting larger. the mega millions jackpot is now $540 million. that's up $40 million from yesterday. it's expected to rise higher as millions of americans catch lotto fever ahead of tomorrow night's big drawing. when we come back, the people already striking it rich. a new modern-day gold rush.

finally, at a time when a lot of americans are struggling just to get by, one nevada city is in the midst of an economic renaissance, far from the bright lights and casinos of the vegas strip. as the price of gold remains sky high, the mines in elco are booming, and folks are coming from far and wide to get in on the action.

nbc's kristen dahlgren reports. >> dawn in elco, nevada, and it's not just the sun casting the glow. there's gold in these hills, and for mine workers like devon judy, these are good times. >> i feel fortunate, that's for sure. i know a lot of americans out there don't. >> the mines are adding hundreds of jobs. so devon, a 22-year-old combat veteran, picked up and moved here. he drives a huge hauler all day, and at night, goes home to his family with a $60,000 a year paycheck he says he couldn't have found elsewhere. >> what do you think your daughter's life is going to be like here? >> very well provided for. >> so many have come to elco, there's a waiting list at the rv park. >> on this side, we have over 100 spaces. >> full? >> it's all full. >> and construction companies can't build housing fast enough. >> everybody in elco, we work for the mining industry. if don't care if you're selling doughnuts, this is the industry we're in. >> take a look at how tiny the

massive trucks look from here. that gives you some idea of the scale of this operation. this is what they call a pit. this is about a mile wide, a third of a mile deep, and since the early '80s, they have taken billions of dollars in gold from here. but that gold is microscopic and takes an expensive process to extract. only worth it when the price of gold is high. the mayor says they're cautious with their new-found wealth. >> at $1600, hey, we're smiling. at $200, it's like, oh. you know, what's going to happen? >> this boomtown has seen bust before. ghost towns that dot the west, a constant reminder. >> have you hit water. >> all of the things you want and dream about when you get out of college, you can have here. >> for elco, for now anyway, life is golden. kristen dahlgren, nbc news, elco, nevada. >> that's our broadcast for this thursday night. thank you for being with us. i'm lester holt, in tonight for brian. we hope to see you right back

here tomorrow evening. good night. good evening, everyone. i'm jessica aguirre. >> and i'm raj mathai. they are overwhelmed by the support, not just here in the bay area but around the country. it's been nearly two weeks since 15-year-old sierra lamar disappeared. yet her family remains hopeful. and there are new details tonight. let's bring in nbc bay area's marianne favro who joins us from the command center in morgan hill. good