on our broadcast here tonight, breaking news in the trayvon martin murder investigation. the late release tonight of evidence in the case. hidden risk. the antibiotic people so often ask for by name. tonight, a big warning about potentially fatal consequences for some people who use it. payday. facebook goes public. it's abouto make a lot of people very wealthy, but what about buying facebook stock? and the queen of disco is gone. tonight, remembering the music of an era and the unmistakable voice of donna summer. "nightly news" begins now. good evening. just now tonight, we're getting our first look at the actual

police evidence in the case of the shooting death of trayvon martin. tonight, documents are being released showing what police and the medical examiner found out, including interviews from witnesses, from the night george zimmerman fired his weapon, resulting in the death of an unarmed teenager. for starters, trayvon martin was shot through the heart at close range after the scuffle with zimmerman. it's part of what we learned in the release of evidence tonight. kerry sanders starts us off from sanford, florida, tonight. kerry, good evening. >> brian, tonight, we're getting a never before seen look at some photos of defendant george zimmer taken hours after the shooting. also, where trayvon martin had gone to buy skittles and an iced tea. also this surveillance video from the club house. there are photos of the crime scene where he shot the unarmed

teenager on february 26th. and then there's this photo of the weapon zimmerman had with him that night. now, one of the investigators in an interview says with trayvon martin's father, this interview was on february 28th, innight of the shooter, quote, i asked . imartinf the voice calling for help was that of his son. mr. martin clearly emotional, impacted byhert recording, qu t quietly responded, no. now, trayvon martin's mother listened to that tape and clearly identified the person calling out for help as her son. and in another document, a witness told police the screams were coming from george zimmerman, and trayvon martin was throwing punches mma style, that's mixed martial arts. also tonight, from the autopsy report, toxicology tests that suggest that there was thc in his blood. that means that he may have been smoking marijuana. no surprise since he had been

suspend eed from school for havg that in his book bag. >> kerry sanders starting us off tonight. thanks. today in north carolina, a tale of two very different john edwards. was he a bad husband or something worse? was he a criminal. those two portraits were presented to the jury in closing arguments in the edwards campaign finance trial. lisa myers reports from federal court in greensboro. arriving with his daughter cate and his parents, john edwards looked more tense than usual for what his lawyer called the most important day of his life. prosecutor robert higdon laid out the government's case using edwards' own campaign rhetoric against him. >> there are still two different americas. one for all the families who get whatever they need whenever they want it and one for everyone else. >> higdon said in using almost $1 million from wealthy donors to hide his mistress, edwards violated campaign laws designed to bring the two americas together at election time. john edwards forgot his own

rhetoric. his voice indignant, he detailed the scheme to protect edwards' political ambitions by hiding hunter, quote, until the election was over and his wife passed away. >> his most important point was that he had to know the cover up was a crime. he was too smart not to, and the convoluted money trail proved it. >> responding to the government, edwards' defense lawyer abbe lowell asked jurors to distinguish between a sin and afulany and said edwards already is serving a life sentence for what he has done to his family. lowell tried to pick apart the government's case saying it's based largely on the star witness, andrew young. john's conduct is shameful, but it's human. young's lies on the stand and the government sponsoring those lies is worse, lowell said. lowell said edwards was wealthy enough to use his own money to pay hunter's expenses, but he couldn't. he was hiding the affair from mrs. edwards. at times emotional, lowell said for all his wrongs, edwards

still can do good. please let this sad chapter end and stop with your verdict of not guilty. the jury begins deliberations tomorrow and will decide whether edwards gets to go on with his life or becomes a convicted felon. if found guilty, he could face up to 30 years in prison, brian. >> lisa myers, greensboro, north carolina, tonight. thanks. in presidential politics, there was an explosive headline this morning. the "new york times" reporting that a republican super pac was considering an expensive anti-obama ad campaign that would have put the issue of race front and center in the campaign and linked the president to some of the more controversial statements by his former pastor, jeremiah wright. tonight, republicans including mitt romney are trying to distance themselves from that strategy. but as nbc's peter alexander reports, it's the latest evidence of the potential power of big money this year in politics. >> campaigning today in florida, mitt romney tried to distance

himself from a super pac's proposal for a $10 million ad campaign designed to renew attention on president obama's ties to his controversial former pastor, reverend jeremiah wright. >> i want to make it very clear i repudiate that effort. i think it's the wrong course for a pac or a campaign. i hope that our campaigns can respectively be about the future. >> a leaked copy of the 54-page proposal titled "the defeat of barack hussein obama" first reported in the "new york times," was presented this week to the super pac funded by joe ricketts, whose family owns the chicago cubs. the proposal refers to president obama as the metrosexual black abraham lincoln and lay out a storyboard for a short film to publicize wright's racially incendiary sermons, including this remark after 9/11. >> america's chickens coming home to roost.

>> in a statement to nbc news today, the super pac insists the ads won't air, adding the proposed campaign reflects an approach to politics that mr. ricketts rejects, and it was never a plan to be accepted. still, on a day the romney campaign wanted the focus to be on its raising more than $40 million last month, a reignited debate over how super pacs can both help and hurt a campaign. >> voters do not distinguish between ads coming from the campaign versus the super pacs, so candidates run the risk of being held accountable for bad things these super pacs do. >> romney today tried to cast himself as the one taking the moral high ground, characterizing his new ad out tomorrow as positive and criticizing the obama campaign for what he called character assassination. peter alexander, nbc news, washington. from silicon valley to the big wall street banks to the individual investor, the big story tonight is facebook going public. the social networking giants

priced its initial public stock offering tonight at $38 a share, which is the upper end of what a lot of the analysts were estimating. that will give the company a valuation of $104 billion. making it the biggest ever valuation of a company in its public debut. facebook has 900 million users around the world. and at least some of them will want to own the stock, which begins trading on the nasdaq tomorrow. with us tonight from facebook corporate headquarters in california, cnbc's technology correspondent john fort, and john, how does this work? who gets first crack, and what about the folks everywhere who might want a share or two or facebook stock? >> as you suggested, if you're online, chances are facebook owns a piece of you, your pictures, your friend list. here's a chance to own a piece of facebook. once it goes ipo tomorrow around 11:00 eastern in the morning, it will be just like any other stock. anybody can go online from their account and buy it.

the question is, whether it's a good investment. this isn't some spring chicken company that nobody knows about. it's going public, as you said, as a very, very expensive company. the people who are really going to make out are the early investors who are selling their shares to the rest of us, the public, tomorrow. mark zuckerberg is trying to make sure things don't change too much when the company goes public. that's why he wore his hoodie to wall street, why he's going to be here with the company's software engineers coding through the night, writing code, not counting their paper profits. brian. >> john with us from menlo park, california. corporate headquarters tonight, john, thanks. overseas now to the uncertainty surrounding greece and the fears that the economic meltdown there could cause major chaos in markets everywhere, including, of course, this country. for many ordinary hard working greek citizens, this nightmare has already happened. nbc's stephanie gosk reports from athens for us tonight. >> a rare bright spot in athens.

the olympic torch handed off to the organizers of london 2012. but on the other side of town, evidence of the now daily struggle just to get by. many of these women lining up for free milk, frozen chicken, and detergent, aren't used to being poor. >> you're scared. me and my all my country are scared. >> to avoid bankruptcy and remain part of the eurozone. greece agreed to make drastic budget cuts. protesters hit the streets over slashed pensions, jobs, and the minimum wage. when greeks went to the polls this month, they gave a drubbing to the political parties that agreed to the bailout plan. the election left the parliament split, unable to form a government. with the bailout plan now in jeopardy, they have to vote again. the new elections are scheduled for june 17th, but until a government is formed in this country, there is uncertainty, and uncertainty breeds fear. this week, they felt it at the banks.

on monday alone, greeks withdrew 700 million euros from their banks. american jennifer took out her entire savings in cash because she worries greece will return to its old currency, the drachma. >> the time was right to make that move. >> the return to the drachma and the impact it would have on europe is a concern for the whole world, including the u.s. >> americans should care because this is the biggest economy of the world, their biggest export market. >> at the donation center, this woman is fed up with the politicians. >> they all shout, we love our country. okay, do something about it. we don't see that. >> what she sees is the need for help growing day by day. stephanie gosk, nbc news, athens. back in this country, there have been a lot of warnings that this wildfire season is going to be very bad, perhaps even historic because of the lack of

winter precip and snow pack. so far it's bad in arizona where the big fires grew even larger. as you may know, western fires all get names based on their point of origin. the so-called gladiator fire has moved toward the historic mining town of crown king. residents there have been evacuated, and colorado officials have evacuated dozens of homes near ft. collins as the hewlett fire there has burned over 5,000 acres. and we have been telling you about the first wave of debris from last year's japanese tsunami washing up on american shores. there's more to come, and today on capitol hill, at a senate hearing, we learned what is sure to be a strain when the debris comes ashore in bulk. the states and not the federal government are going to be forced to pay for the majority of cleanup costs. still ahead as we continue along the way tonight. if you're one of the patients who asks the doctor for a z-pak by name, something serious you should know about. and later, they called her the queen of disco.

tonight, we'll remember the music and the voice of a woman who helped define an entire musical era.

today's health news story hit a lot of us where we live. it's about the antibiotic a lot of us ask for by name. the z-pak, as you may know. it's one where you take two the first day and then one a day for four days after that. and it works for a lot of people. but tonight, new research suggests the z-pak may be a terrible idea for some patients. our report tonight from our chief medical editor, dr. nancy snyderman. >> in this busy emergency room in brooklyn, one of the most widely prescribed drugs is the antibiotic, azithromycin. >> it generally has been a safe drug we have used for many years. >> also known as zithromax or a z-pak, it's a five-day course of antibiotics prescribed for every

from sinus problems to bronchitis. there have been reports of problems with this drug with patients with heart disease. the new england journal of medicine reports researchers at vanderbilt university have found that the drug could increase the risk of sudden cardiac death in some patients. >> there's a lot of smoke with regard to whether or not there are heart problems and we wanted to see if there was any fire. and we found that there was. >> for patients who have heart disease, severe diabetes and other risk factors, the drug can cause an abnormal and even fatal heart rhythm. >> we saw a relatively small number of deaths in the azithromycin users but it was 2.5 times as many as would be expected. >> last year, doctors wrote over 55 million prescriptions in the united states for azithromycin. globally, sales totaled $1.8 billion. pfizer makes zithromax and released a statement today.

we are thoroughly reviewing this observional study and patient safety is of the utmost importance to pfizer. back in brooklyn, doctors still see azithromycin as an important medication. >> for my practice, i will be more vigilant in looking for signs of cardiac disease for patients for whom i'm prescribing azithromycin. >> patients should talk to their doctors about considering an alternative antibiotic to z-pak, and for those with high cholesterol, risk factors like diabetes, high blood pressure, anything else that could put your heart at risk, is a conversation worth having and a reminder, this is an antibiotic. it doesn't work for a common cold. not for viruses and a second-line drug of choice. >> this will now get the attention of all physicians. nancy, thank you, as always. up next tonight, a new tipping point. something has just happened in america for the first time in our history. it changes our society forever. it says a lot about who we are. e

a coroner's report out today says mary kennedy, the estranged wife of robert kennedy jr., died from asphyxiation. she committed suicide. she was found yesterday hanging in a barn on the ground of their home in bedford, new york, north of new york city. the couple's four children range in age from 11 to 17. all of them were out of the house when it happened. there is a new picture tonight of just who we are and how the face of america has just changed, perhaps forever. a picture that is emerging in new census numbers showing that the word minority may no longer apply. our report tonight from nbc's anne thompson. >> the sound is the same. but how america looks is beginning to change. the u.s. census bureau says for the first time, minorities make up the majority of the

population under the age of 1. 50.4% of these very young americans. though the nation's overall population is still predominantly white, the census bureau reports minorities are the majority in four states, hawaii, california, new mexico, texas, and the district of columbia. the biggest minority group is hispanics, followed by african-americans and asians. growing the fastest from 2010 to 2011, hispanics. up 3.1%, followed closely by asians, native hawaiians and other pacific islanders, then native americans. >> if we look at the data, what we're really talking about is not just questions of race and culture but really about how we think about the contributions that this diverse populous can make. >> brooklyn's medical center delivers 8,000 babies a year, the most in new york state. it prints information in ten different languages.

and has on hand interpreters in 70 languages to meet the needs of its multicultural population. the changes that are seen here and across the country do not end at the maternity ward. there are potentially big impacts on our politics, our economy, and our education system. today, fewer hispanics and african-americans have high school and college degrees than whites, limiting their economic opportunities. >> when i think about the census data, i'm more concerned with class, i'm more concerned with poverty, more kearns with issues that cross this construct of race. >> issues for all as the proportions in this melting pot begin to change. anne thompson, nbc news, brooklyn, new york. up next tonight, the unmistakable voice of donna summer is now gone. tonight, we remember her legacy and the music of an entire era.

a legend in music is gone tonight. donna summer, who pioneers pop songs with electronic backing that are among the staples of music still today and was the voice and face of the era of disco. she fought a long battle with

cancer and died today at the age of 63. our look back tonight from nbc's rehema ellis. ♪ bad girls >> for generations of partygoers in the '70s and '80s, donna summer was the queen of disco. ♪ come on baby >> when billboard magazine created its disco chart in 1975, summer was consistently at the top. with songs everyone has come to know. ♪ she works hard for the money ♪ looking for some hot stuff >> summer is a five-time grammy winner with a star on the hollywood walk of fame. she even won an academy award for "last dance." she's considered the first cross over artist in pop music history. >> donna summer did more than anyone else to make disco cool, to take it out of the underground clubs and onto the pop charts. that was an incredibly important thing that revolutionized pop music for more than a decade, at

least. >> born on new year's eve, 1948, she discovered her voice singing gospel music as a child. >> i was in church and i started singer and all of a sudden, i opened my mouth and this voice came catapulting out of my body. >> eventually, she made her way into acting in musicals. >> i paid my dues. all i'm asking for is a chance. >> it was the sexy pop dance rock music sound that made her an international star. >> i think her music, those anthems she sang, were anthems of equality and empowerment for everybody. ♪ last chance for love >> of all her hits, donna summer said "last dance" was her favorite song, a song that will keep future generations of fans dancing. rehema ellis, nbc news, new york. >> that's our broadcast on a thursday night. thank you for being here with us. i'm brian williams. we hope you'll join us right

back here tomorrow evening. good night. good evening and thanks for joining us. i'm raj mathai. >> and i'm jessica aguirry. >> he survived seven days without food or water lying in heavy brush off highway 101 in south san jose. today the family of michael sanchez jr. is asking why it took so long to locate the 25-year-old. sanchez was eventually found unconscious near the hellyer avenue exit. tonight he's in a coma, and his family has lots of questions for the chp.