on the broadcast tonight, breaking news. the latest tragedy for the kennedy family. the estranged wife of rfk jr. has been found dead tonight. the defense rests in the john edwards trial without calling him, his daughter, or mistress to the stand. what will it mean for the former presidential candidate? >> the investigation, medical reports shedding new light on the trayvon martin murder case. does it help or hurt george zimmerman's claim he acted in self defense? it is a breakthrough. good news about treating kids with cancer. and empty nest. the spectacular homecoming in california, but what has happened to the legendary swallows of capistrano? "nightly news" begins now.

good evening. shortly before going on the air tonight, we learned of another tragedy to strike the kennedy family. mary kennedy, the mother of four children of robert f. kennedy jr. has been found dead at the family's home in bedford new york, north of new york city. the estranged wife of the son of the late senator from new york suffered some public struggles in recent year, including several brushes with the law. but again, another tragedy for this prominent american family. nbc's andrea mitchell has more from our washington newsroom on what we know at this hour. andrea, good evening. >> good evening, brian. mary kennedy's death, according to local reports, possibly a suicide, is only the latest tragedy to afflict a family that has known far too many. mary richardson kennedy, the second wife of robert kennedy jr., and mother of their four children, was found in

her westchester county home. local police said she was in one of the buildings in the bedford, new york, prop aert. she was 52 years old. they separated three years ago. there had been incidents, at least one arrest on suspicion of driving while intoxicated, three days after the kennedys officially separated in 2010. mary kennedy crashed her car and failed a sobriety test, according to police reports, eventually pleading guilty to a lesser charge and paying a $500 fine. in recent years, her husband, a lawyer and president of the environmental group, water keeper alliance, has been seen often with actress cheryl hines with whom he's worked closely on environment 8 issue. robert f. kennedy has lived with violence throughout his life. he was 9 years old when his uncle was assassinated. only 14 when his own father was gunned down in june of 1968. on the night of his victory in the california presidential primaries. robert f. kennedy jr. lost two younger brothers.

david died of a drug overdose in easter weekend in a palm beach hotel in 1984. michael was killed in a skiing accident in aspen in 1997. then the cousins. john f. kennedy jr. lost in a plane crash in 1999. cara, teddy kennedy's daughter, of a heart attack only last year, and of course the loss of his beloved uncle teddy three years ago. mary kennedy's family said, quote, we deeply regret the death of our beloved sister mary whose radiance and creative spirit will be sorely missed by those who loved her. our heart goes out to our children who she loved without reservation. the family's young children range in age from 10 to 17. brian. >> from washington, andrea mitchell starting us off with this late news tonight. andrea, thanks. now to north carolina where the defense has rested in the john edwards trial without the defendant, his daughter, or mistress taking the stand. nbc's lisa myers has been covering the trial and joined us tonight from the courthouse in

greensboro. lisa, good evening. >> good evening, brian. edwards' lawyers abruptly rested their case after little more than two days and without calling any marquee witnesses. seemingly confident they have punched enough holes in the government's case to avoid a conviction. when john edwards arrived today, his daughter cate who has been constantly by his side, was not with him. cate was willing to testify for her father, but the defense opted not to call her. >> if you put your daughter on the stand and you're not willing to take the stand, that sends a pretty significant negative message to the jury. >> john edwards, who rose to fame through his skills of persuasion, decided to remain silent with his freedom on the line, rather than be cross-examined by prosecutors about his lies. but analysts say not testifying also carries risks. >> the gamble is that the jury would have expected to see john edwards take the stand and say

to them, look them in the eye under oath and say i never thought i was committing a crime. >> less surprising, the decision not to call the woman at the center of the scandal, rielle hunter, who the defense worried would remind the jury of all they dislike about edwards. over the course of the trial, the defense all but demolished the credibility of edwards' chief accuser, andrew young, revealing he pocketed most of the money the government claims went to hide hunter. edwards' defense is focused on the fine points of campaign finance law. and the unprecedented nature of the prosecution. the government alleged money to hide hunter amounted to illegal contributions to edwards, which he denies. after 31 witnesses, some analysts still see a big hole in the government's case. >> they have to show a willful violation. that's always been a challenge, and there's no evidence that john edwards told anyone or even thought he was committing a crime.

>> closing arguments are tomorrow, and the jury is expected to begin deliberations on friday to write what will be the final chapter in a devastating fall from grace. brian. >> lisa myers in greensboro, north carolina, tonight. lisa, thanks. >> with us in the studios, our chief legal correspondent savannah guthrie. savannah, how likely was it really that we were going to see on the stand either john edwards or his daughter cate or rielle hunter? >> cate edwards seemed like in the realm of possibility, rielle hunter and john edwards were both much bigger gambles. edwards in particularly would have really transformed the case into a one-witness case. it would have risen and fallen on his credibility. and the defense made the calculation they would rather focus on the weakness in the prosecution's case, specifically andrew young, their star witness. they want to argue he's the one with the credibility problems, who can't be believed, who admitting lying and taking most of this cover up money. but i have to believe that the

defense lawyers tonight are sweating it a little bit. here they are about to send this case to a jury, case they could have gotten a plea agreement on, but they turned down, took the gamble, hoping it would get dismissed before indictment, dismissed before the judge before trial, that didn't happen. now it's going to a jury, anything can happen. >> a veteran trial lawyer at the center of this, of course, decided to go to trial in the end. thanks as always. there are new medical reports out tonight that seem to tell two different stories of what happened that night in sanfo sanford, florida, the night that george zimmerman shot and killed trayvon martin. our national investigative correspondent michael isikoff reports from sanford. >> florida teenager trayvon martin died from a single bullet wound to his chest. fired from a gun at intermediate range, according to an autopsy report prepared by a medical examiner and reviewed today by nbc news. there was one other fresh injury on martin's body, according to the report, an abrasion, no more

than a quarter of an inch in size to his left ring finger below the knuckle. as for the man with whom he struggled that night and is now charged in his death, george zimmerman, he, too, suffered injuries, according to a separate medical report prepared by his family doctor the day after the shooting. that report also reviewed today by nbc news, states that zimmerman had a likely broken nose, as well as swelling, black eyes, and scalp lacerations, but there were no sutures needed. these reports are only a small piece of a mountain of evidence about to be made public. up to 300 pages and 67 cds of witness statements, surveillance videos and other material. as the evidence dribbles out, it's raising as many questions about what happened that night as answers. >> it's possible the defense will be able to use this to indicate that trayvon martin was in some ways the aggressor. if he's the aggressor, their story would be that zimmerman was defending himself, in which case he would be covered by

stand your ground immunity. >> but a lawyer for trayvon martin's family said the injuries to zimmerman prove nothing because zimmerman a neighborhood watch volunteer, started the confrontation in the first place. >> what we know from the depth of evidence is that george zimmerman got out of his car with a 9 millimeter gun and pursued a teenager, so he george zimmerman, said in his own words, was running away from him. >> as the evidence continues to emrm in this highly charged case, the dueling narratives are only likely to intensify. michael isikoff, nbc news, sanford, florida. >> a lot of the coverage of health news so far this week has been dominated by the story of a young woman from georgia with a flesh eating bacteria, and now a second woman, a new mother, has been diagnosed. our chief medical editor, dr. nancy snyderman, has more on this latest case and whatever everyone needs to know. >> last week, lana celebrated

the birth of her twins, ian and abigail, but just 13 hours after leaving the hospital, she was rushed to greenville memorial hospital in south carolina. >> she just kept getting worse. >> unrelated to her pregnancy, she contracted a bacterium that causes a rare condition commonly known as flesh eating bacterial infection. no one knows how she got it. >> we are asking people to continue to pray for her and lift her up. >> in another case, 24-year-old amy copeland continues to fight the very same infection. the graduate student suffered a large cut on her leg after a homemade zip line snapped and she fell into a river. she's still critical. surgeons have already amputated one leg and may need to remove her fingers. this type of infection could be caused by several types of bacteria, but they all have one thing in common, a deadly toxin that destroys the body's tissue.

>> as it breaks down the tissue, it has a high way, an aggressive highway it can zoom up and spread to the rest of the body. >> these flesh eating infections are rare, between 500 and 1,000 cases a year in the u.s., but they're disproportionately lethal. a quarter of patients who contract the infection will die. to minimize your risk, as with any cut, thoroughly wash the area with soap and water and apply an antibiotic. if it becomes red, swollen, tender and more painful, it's time to head to the emergency room. >> pain out of proportion to the site of a wound is very important in these types of infections. it's a warning sign the infection is much deeper and really needs to have a professional eye looking at it. these are common bacteria with uncommon consequences, but a reminder if the pain is disproportionate to the wound, you head to the emergency room because the treatment, brian, is intravenous antibiotics and aggressive surgical treatment to get the bad issue removed. >> as you point out, rare, but

very scary. >> but pay attention. >> dr. nancy snyderman, thank you, as always. crews are fighting to contain fires in arizona burning over 27 square miles including stubborn fires in the tanto national forest north of phoenix. they're gobbling up ponderosa pine and scrub brush along the way. as the weather channel discovered today, the smoke and vapor visible from space is blowing up into what they call pyrocumulus clouds over arizona. almost 1,000 firefighters are in the fight on the ground and in the air. the shoe company skechers said today it would pay $40 million to settle up charges that its tone-up sneakers do not do for your backside what was advertised by the likes of kim kardashian, who appeared in a super bowl ad for them. federal trade commission says people who bought tone-ups, shape-ups or resistance runners will now be eligible for a refund as a result. still ahead as we continue tonight, good news in the fight

against cancer. a 6-year-old's remarkable turnaround. how his story may offer new hope for others fighting for their lives as well. and later, what happened to the famous swallows that used to come home to capistrano? tonight, the new push to get them back.

in additional health news a moving success story about a rare childhood cancer that was very hard to treat until doctors tried a dug developed for something else and found it works, as it often the case when searching for a cure. and this could be pointing the way toward what many scientists see as the future of all cancer treatment. the story from our chief science correspondent robert bazell.

>> zach witt is an active 6-year-old. but 18 months ago, he was struck with a rare form of lymphoma. the disease usually responds to a harsh chemo ththerapy regime,d at first zach got better, but the cancer returned. >> he would literally sleep all day. he had a constant fever. >> his bicycle, leaning against the barn. i just thought, you know, he might never ride that bicycle again. >> doctors administered an even stronger combination of drugs, but they didn't work either. then suddenly, there was a glimmer of hope. doctors here at children's hospital of philadelphia realized zach's tumor had a genetic mutation and that was the target of a drug that was already on the market to treat lung cancer. that drug only helps about 10% of lung cancer patients. >> can i feel your tummy? >> this doctor and her team were

already using it to treat another rare childhood cancer. they got funding to try it in eight lymphoma patients, including zach. three days into the treatment, a remarkable change. >> he ran down the hall to the playroom. i stood there like, i can't believe this. >> all of the black, which represented the cancer cells, is completely gone. >> scans show the cancer had disappeared in 7 of the 8 children. the results may soon make life very different for children diagnosed with this form of lymphoma. >> we're now rapidly moving this up front so that we can provide this therapy for newly diagnosed patients with lymphoma. >> who may never have to have chemotherapy? >> it's certainly a very realistic possibility, and that's our vision. >> doctors have been working for years toward gene-based personalized cancer treatment. zach who is now riding the bike that once sat idle, is at least one dream come true.

robert bazell, nbc news, philadelphia. up next here tonight, another reason for coffee drinkers to embrace their daily addiction. and in the agony of defeat, a gleaming father/daughter moment emerges.

there was not a dry eye in the east room of the white house today. it's always the most emotional of white house ceremonies when the president awards the medal of honor. made worse today by the facts it was posthumously awarded to sergeant leslie sabal jr., who died fighting for his army comrades in cambodia in the vietnam war. his widow accepted the medal, delayed 42 years because the paperwork was lost. the room was filled with current officers, fellow veterans from the 101st airborne and fellow

medal of honor recipients from the vietnam war. this next item will either bring business to virgin atlantic or keep customers away. passengers are now able to use their cell phones to make and receive calls while aloft. it's just a few planes at first, thankfully there's limited band width so just a few passengers at a time can use their phones. and the service depends on your overseas carrier. you can just hear the sound of, "can you hear me now?" >> there's always a coffee study that justifies just about any behavior. according to the latest study, a big one published in the new england journal of medicine, coffee drinkers are slightly more likely to live longer than non-coffee people, and it doesn't matter, they say, if it's regular or decaf. >> a couple of great videos getting heavy circulation on the web. including this one. sometimes as strong as dads are, they suffer heartache. that was the case when this dutch soccer player was crushed by defeat in the league finals. his daughter wearing his jersey, saw it as her job to comfort her dad on the field, who can now be

consoled at least by the fact he's been blessed with such a good daughter. a second video, dramatic change of subject. cats are notoriously secretive, like while you find them repelling off the top of the refrigerator when you get home. but this kind of unmasks their secrets for good. as part of a research project, they attached tiny camrays to house cats. now we can see everything. framed, of course, by their whiskers, trips inside the storm drain, climbing on the roof of the house, encountering a possum, and other former animals, still very little explanation for any of their behavior. we have posted both videos tonight on our website. up next here this evening, no place like home, so will the legendary swallows really return to capistrano?

few sights are as spectacular as the return in unison of the famous swallows of capistrano. from argentina every march to their home in california. it's a major attraction for visitors, but in recent years, the swallows haven't been returning, and there's a new push under way to lure them back. our report tonight from nbc's miguel almaguer.

>> it's known as the jewel of california's missions, san juan capistrano, steeped in 200 years of history, renowned for its beauty and famous for its cliff swallows. >> a song in 1940 made their annual migration legendary. >> there are still some things we can count on. one of them is the swallows coming back to capistrano. >> for decades, the swallows arrived in the spring and then flew back to argentina in the fall. >> the swallows are intertwined with our story and our relevance to society. we want to make sure that people see our little birds and some see the mission. >> today, the swallows are gone. >> i can't even see them. >> the mission underwent renovations, preservation efforts stabilized the crumbling walls, but nests had to be removed, and the birds stayed away. retrofitting was just one of the issues. the mission used to sit on wide open prairie land, but

urbanization changed that. another reason why the swallows left. now, tucked beneath the bell tower, biologists are using the sound of love to lure the swallows home. >> we're playing back the birds' courtship songs. >> biologist charles brown is leading the mission. he studied cliff swallows for 30 years. >> 30.5. >> and believes the birds will migrate back to capistrano. >> it may not be this year or may not even be next year, but i think if we keep trying long enough, they will realize it's a good place to nest, as they did in the past. >> there is progress. the swallows are closing in. nesting just a quarter mile from the mission. close enough to give the faithful hope, to remind them of the time when presidents made the voyage to capistrano. decades later, new sounds just may bring the swallows back. miguel almaguer, nbc news, san juan capistrano.

>> and that's our broadcast on a wednesday night. thank you for being here with us. i'm brian williams. and of course, we hope to see you right back here tomorrow evening. good night. thanks for joining us this evening. i'm jessica aguirre. >> and i'm raj mathai. new information tonight about that century old cemetery unearthed during a construction dig at a well-known bay area hospital. santa claira county officials sy there could be more than 1,000 people buried in the hidden graveyard. it's a story we first broke yesterday. nbc bay area's kimberly tere is in san jose tonight with the noop details. kimberly? >> reporter: raj,