Announcer from nbc news World Headquarters in new york, this is nbc nightly news with lester holt. Good evening. We have seen political standoffs of all kinds in washington, but nothing like what is playing out right now in the chambers of the house of representatives. Oldfashioned sitin led by a civil rights icon. Democratic representatives literally occupying the house floor, refusing to budge until a gun control bill is brought up for debate. Social media continuing to provide images of the revolt, even after housecontrolled tv cameras were ordered turned off. Nbcs Peter Alexander is at the capitol right now with the latest. Not next year, but now today reporter an unprecedented demonstration, dozens of democrats today calling for a vote on gun control. Rise up, americans. This cannot stand. We will occupy this floor. Reporter disrupting the house session. The house will be in order. Reporter republicans in retreat, forced to go into recess, cameras showing the protest. The cameras controlled by the Republican House speaker. Democrats in rebellion taking to social media to broadcast their message, violating house rules. They will not silence our voice. Reporter spearheading the sitin, john lewis, an icon of the civil rights struggle. Then you were fighting for civil rights. What right are you fighting for now . Were fighting for the rights of people to live without fear for gun industry lens. Reporter the president punctuating the point, thanking lewis for his leadership. As word spread, the chorus grew. Democrat Keith Allison abruptly leaving a meeting after receiving this note. Your mom called and wants you on the floor. Democrats commandeering the chamber for hours, joined by Senate Colleagues days after their filibuster forced a gun vote, which failed. Todays rallying cry, no bill, no break. Their demand, Speaker Paul Ryan working through next weeks planned recess, until the house votes on background checks and a no fly, no buy bill. Republicans balking. I dont mind voting every day against a bill that would take away Second Amendment rights from folks. Reporter speaker ryan speaking out late tonight. This is trying to get attention. I just left the House Chamber where democrats are Still Holding court this hour. Paul ryans office said no votes are scheduled. Democrats insist it will stay as long as it takes. Unclear how the stalemate over guns ends. An extraordinary scene. Peter, thank you. Today donald trump is trying to jumpstart his campaign after a very rough few weeks. Trump went on offense, unleashing a wide ranging takedown of Hillary Clintons record. But nbc news has found many of the claims he made were misleading or outright false. Hallie jackson is separating fact from fiction. Reporter donald trump finally on offense after days defending his campaign. Hillary clinton may be the most corrupt person ever to seek the presidency of the united states. Reporter hes working to define Hillary Clinton as a creature of wall street, and washington. Her Campaign Slogan is, im with her. You know what my response is to that . Im with you, the american people. Reporter trump never one to mince words, though today not all of them were true. Her server was easily hacked by foreign governments. Reporter but a state Department Inspector generals report said it found no such evidence, only routine fishing. No Government Official said her emails were hacked. And on benghazi . I mean, she what she did with him was absolutely horrible. He was left helpless to die as Hillary Clinton soundly slept in her bed. Reporter thats not what clinton told the select committee this fall, under oath. I did not sleep all night. I was very much focused on what we were doing. Reporter the hearings revealing she was still at the state department when the attack started to unfold in the early afternoon. Later emailing her daughter from home shortly before midnight. Trump also accused clinton of doing favors for cash at the state department. Hillary clinton has perfected the politics of personal profit, and even theft. Reporter trump leaning heavily on the book clinton cash. But that books author admits theres no evidence to prove those allegations. I guess my speech yesterday must have gotten under his skin. Reporter one day after attacking her rival on his business record, clinton again targeting trump. Hes going after me personally because he has no answers on the substance. Reporter clinton now picking up new support from the National Security adviser who worked with republicans, president ford and george h. W. Bush. Lester . Hallie, thank you. One of trumps former rivals for the gop nomination said today he is reversing court and decided he will in fact run for reelection to the senate. Senator marco rubio had previously insisted he would not run. But he came under pretty intense pressure from fellow gop senators to change his mind and help them keep the majority. Rubio faces a tough reelection fight. In minnesota today, former speaker of the house Dennis Hastert reporting to a federal prison to begin serving his 15month sentence in a hush money case brought to light revelations he sexually abused at least four boys while he was a High School Wrestling coach decades ago. The Illinois Republican is one of the highest ranking american politicians ever to go to prison. Late word of a tragic discovery in the urgent search for a family missing off the florida coast. One person has been found dead, after a father and his three teenage children vanished in their boat over the weekend. Nbcs Gabe Gutierrez has more for us. Reporter tonight a desperate search at sea for a family of four. One of the coast guard helicopters located a deceased person. On fathers day, ace kimberly and his three teenage children set out from Sarasota Florida and south to ft. Myers. They planned to meet his brother and repair their 29foot sailboat. They were usually together. Tightknit family for sure. Reporter around 3 00 p. M. , trouble. Kimberly called his brother reporting sixfoot seas, and saying he was attempting to survive with his children. Fwhefr we never received a distress call. This morning a discouraging story. Reporter this morning a discouraging discovery. During the night, search pattern, fixedwing aircraft located a debris field. Reporter debris 33 miles offshore matching items from the missing vessel the family was living on for the past year. Four water jugs tied together, ten any shoes, a basketball and six of their seven life vests. And later the two kayaks they had been towing. That is a dire finding. It is also heartening it was right in the middle of our search pattern. We know that we were searching in approximately the right area. Reporter just last year teenagers perry cohen and austin disappeared off the east coast of florida. Now both of their families issuing written statements, saying theyre praying for the kimberlys. We do everything we can for as long as we can. Reporter a frantic search as a terrified family members still at sea. Dangerous weather extremes have tens of millions on alert this evening. High temperatures continue to fuel wildfires in the west, while severe storms are threatening to hit the countrys midsection with hail, floods and potential tornadoes into the overnight hours. Weve got it all covered, beginning with blake mccoy in chicago. Blake, good evening. Reporter lester, good evening to you. We are expecting a tornado watch to be issued for chicago and the surrounding areas any minute. Severe weather and high winds expected into the night. Golf ball sized hail pummeling the plains of north dakota. Cracking windshields before moving east, bringing heavy rain to illinois midday, as the first round of storms moved through. Delays and more than 100 cancellations already at ohare. A second round of Severe Weather will bring the threat of tornadoes to the chicago area tonight. So far this year, there have been reports of 657 possible tornadoes. But few have threatened areas as heavily populated as the windy city. 50 Million People at risk for severe storms, including tornadoes, gusty winds, up to 70 miles per hour. Late tonight, from chicago, into ohio, by early tomorrow morning were in the Midatlantic States and then another round of strong storms affect the Midatlantic States by tomorrow evening. Reporter Midatlantic States like delaware were already hit with heavy rainfall tuesday. Flash flooding at this d. C. Metro station had commuters wading home from work. A confirmed tornado damaged these homes just outside baltimore, as millions brace for the latest round of violent summer storms. Blake mccoy, nbc news, chicago. This is Miguel Almaguer in the foothills outside los angeles. Overnight, helicopters hammered flames making a run toward homes. Every fire getting a quick massive response. What may be the only way to save property in whats becoming an epic fire season. Firefighters say conditions couldnt be worse. In the west, multiple fires burning faster, hotter, and more explosive than ever before. Today infernos are fueled by heat, wind and parched trees. Theres a lot of tree mortality out there. You know, it makes fire behavior worse. Reporter in california alone, 66 million dead trees killed by drought and bark beetle are turning sparks into mega blazes. The mega fires every year now. Reporter so far this fire season crews have been able to save most homes, though there have been close calls. In an instant, they know that can change. Tonight the fight continues. This, the new normal, in the shifting landscape thats more dangerous than ever. Miguel almaguer, nbc news, los angeles. Dangerous rescue mission at the bottom of the world is being hailed as a success. A plane evacuating workers from the south pole to get medical treatment has just returned after flying through some of the most treacherous conditions imaginable. Nbcs bill neely has more on how it all played out. Reporter it landed on skis on an ice runway. A hug for the pilot. And for the plane, heaters in case the fuel froze. This was a risky rescue in a brutal landscape. A fragile plane carrying two sick workers on the darkest day of the winter. This is the toughest time of year we could possibly be going into antarctica. Its dark 24 hours a day. Very cold. Reporter the windchill temperature, 115 below zero. The machine was to evacuate the workers from the u. S. South pole station. One with a lifethreatening illness. The plane flew 1,500 miles to the base and then back in polar winter. It would have been completely black at the south pole. There would be no lights. Reporter the conditions are horrendous. This, a previous rescue. There is no room for error. I know, because ive been there, eight years ago, in what was considered perfect conditions for a rescue. Antarctica is already the wind iest place iest place earth. 70 mile per hour guests today, and this is midsummer. Today it was midwinter. But the plane landed safely. Its two sick workers now resting at the bottom of the earth before leaving this frozen continent for good. Bill neely, nbc news, london. Several u. S. Navy sailors have been recommended for possible disciplinary action for an embarrassing incident with iran. Youll recall in january, iran released images of those sailors being detained when their boats drifted into iranian territorial waters, in what one military official calls a calamity of errors. All ten were later released. None have been charged, but one person has already been relieved of duty. Were just hours away now from a vote that could send shock waves to the u. S. And around the world. Great britain is on the eve of the socalled brexit vote to determine whether it will leave the european union. The results of the referendum could have a major impact on the American Economy as the fed says it is closely monitoring the situation. An emotional outpouring at a memorial for british lawmaker jo cox fatally shot and stabbed by an attacker last week. Among those paying tribute, ma laly yousafzai herself a survivor of gun violence. Today would have been coxs 42nd birthday. Still ahead tonight, a terrorist scare turns out to be Something Else entirely. A heavily armed mission to rescue a heroin addict. What we know about the plan and the man at the center of it. Also, the trial over one of the most famous songs in the world is now in the hands of a jury. It all began with a traffic stop, and police seizing a trove of weapons. Immediately it raised suspicions of terror. Then the driver told police he was on a rescue mission to save a girl from heroin, which also killed his own daughter. As our Stephanie Gosk reports, its raising questions, is he a crusader or a vigilante . Reporter they were arrested at the entrance to the holland tunnel driving this truck. With loaded weapons, assault rifles and body armor. Today the trio is fighting multiple possession charges each held on bail. The incident sparked terrorism fears, but now it appears john and his team were going to help a 16yearold girl on drugs in brooklyn. They were on their way in to get this girl because she had stated she was high. She wanted to get out. Reporter lynn baker formed an antidrug activist group, enough is enough, four months ago, after his 20yearold daughter died of a heroin overdose. Her death was a call to action for the gun range owner. He spoke out at a town meeting. We have to stand together. We need to take our streets back. Reporter baker said the group enough is enough has rescued dozens of addicts. 27yearold Andrew Miller was one of them. He called kranzy for help in april. Hes on a daytoday mission to save as many kids as he can, and as many parents from getting that phone call that their child has died. Reporter after tuesdays bust, some are calling kranzy a vigilante. On facebook, his posts are often militant. The caption on this photo, knock knock, whos there, your worst nightmare, and im coming in. The ammunition chest seized by police reads, shoot your local heroin dealer. Today baker defended her friend. John is a very caring and tenderhearted man who comes off rough and tough. Reporter tonight all three sit in jail. At least for now, kranzys personal war on heroin is over. Stephanie gosk, nbc news, new york. Were back in a moment with a bigname at athlete skipping the rio olympics off zika virus fears. Hlete skipping the rio olympics off zika virus fears. Tonight a high stakes case involving one of the greatest bands of alltime and one of the greatest songs of alltime is in the hands of a jury in california. The question, did led zeppelin rip off part of stairway to heaven . The band says no, but millions are at stake. Nbc news correspondent tammy likener has details. Reporter it may be the most wellknown opening chords, the center of a copyright lawsuit. Led zeppelin is accused of stealing the opening chords from stairway to heaven from a rock band in the 60s. This is the opening to stairway to heaven. And this is the song torres by spirit. In the courtroom, led zeppelins lead singer said he didnt remember spirit and he and jimmy page came up with a song while sitting at a campfire outside a remote cabin in wales. The Founding Member of spirit wolf died in 1997. According to the complaint, one year before his death he wrote, i would say its a ripoff and the guys made millions of bucks off it and drnt say thank you. Maybe some day their conscience will make them do something about it. When they played all the recordings, it felt magical to be sitting there. People were nodding their heads along, even the jury. Reporter now its up to the jury to decide who owns that stairway to heaven. Tammy lightner, nbc news, los angeles. A major golf star to the growing list of athletes skipping the rio olympics. Rory mcilroy, the fourth ranked golfer in the world is now the biggest name to say he wont play in rio over fears of the zika Virus Outbreak in the region. This is the first time golf will be played at the olympics in over 100 years. When we come back, fans in cleveland going to extreme to catch a glimpse of the new nba champions. The extraordinary bond she shares with her father and a bay area doctor. Peggy vo plus, a Company Tells a customer with too many returns. They dont want her back. Nbc bay area responds. Peggy next close next. Sot finally tonight, a cliffhanger of sorts in cleveland. A longsuffering sports town celebrating the newly crowned nba champs. Over 1 Million People swarmed the streets. Nbc joe fryer shows us. Reporter its only fitting cleveland is home to the rock n roll hall of fame. For today, every block of this jubilant city is truly rocking, and rolling. 2016 world champions, cleveland, ohio reporter by some reports, 1. 3 million fans filled downtown for todays parade and celebration. More than three times clevelands population. The diehards even scaling a parking garage like climbers ascending a mountain to get a better view. Never in my life time would i think i would get to see it. Reporter they languished for 52 years without winning a sports title. A curse now broken after an incredible cavaliers comeback led by their king, lebron james, who rolled through town on a rollsroyce. Im nothing without this group. Im nothing without the coaching staff. Im nothing without the city. Reporter a place thats now swelling with pride. You might know it as cleveland, but today they call it believeland. Joe fryer, nbc news. That is going to do it for us on this wednesday night. Im lester holt. For all of us at nbc news, thank you for watching, and good night. Right now at 6. Ale he told me he remembers a fight. And he dont remember nothing else. Right now at 6 00, a violent end to the nba finals. A warriors fan in surgery today, his family now making a desperate plea for answers. Thank you for joining us tonight. Im peggy bunker in for jessica aguirre. And im raj mathai. Did he fall or was he pushed . The real pain of that loss came amidst the game this fan fell from an upperlevel concourse at the oracle arena. What happened . His family says a fight led to the fall. His family and Police Still Searching for clues and witnesses. Nbc bay areas robert handa is at the oracle this evening. Robert whats the family saying tonight . Reporter well, as you know there was a lot of emotion going on here during game seven sunday. And as weve seen before, bad things can happen when that kind of emotion gets out of hand such as we saw with brian stowe. This time the victims father says his son was just standing too close. Salvator bimbo is recovering today in Highland Hospital in oakland. He lives in los angeles, grew up in San Francisco and came back to the bay area where most of the family still lives to see his beloved warriors in the nba finals. He paid 900 for this ticket to game seven sunday in the upperlevel section 220 of oracle arena. Right after the game an alleged