Some submerged three or four feet. Most of the residents left here had to be rescued in the middle of the night. They were hoping to get back no their the rain still coming down so hard theres no chance of that. Got it over here over the top. Reporter beyond louisiana potential illinois. 22 Million People stretching 1,000 miles in. San antonio a school bus rounding a curve lost control and flipped. The rainslicked roads thought to be the cause. Two children and adults escaped serious injury. Throughout the region downed trees have toppled power lines leaving 35,000 rout electricity, and the rain keeps coming. Taylortown, louisiana, recorded more than 14 inches. With more on the way. The fire chief says in a quarter saleofthecentury hes rarely steen this bad. We do not expect to have as much rain as we had, and without any time for it to drain off. Ketchum and his brotherinlaw borrowed a boat to check out his neighbors. All were objection okay, but they lost two horses and a dozen goats in the fast rising waters. 1991 it did the exact same thing it is now. Reporter and just a short time ago, a new mandatory Evacuation Order was issued. This one for 3,500 homes here over fears one of the bayous would overtake its levee of, further devastating this community. Janet shamlian, thank you. Tonight donald trump is looking to take out his rivals for the republican nomination once and for all after overcoming a barrage of attacks and scoring decisive victories in three of four states up for grabs last night and hillary clinton, hoping to turn her attention to trump, scored a landslide victory in mississippi, but Bernie Sanders pulled off the biggest shocker of the night in michigan. High drama on both sides. Lets start with nbcs Hallie Jackson on the gop campaign in miami. Hello, hallie. Reporter lester, good evening. Racking up more delegates in a sign those establishment attacks arent working, not yet at least. His rivals best shot against trump happening in the next six days as we build towards showdowns in ohio and here in florida where 99 delegates are up for grabs, and tonight its trump looking most likely to take them home. Donald trump now ready for the final round to put this fight away. Thats the ultimate way of doing it. You knock them out. If you knock them out, nothing can happen. Reporter you want to go for a knockout . Id rather go for a knockout. Reporter trump in one corner and in the or the movement to try to stop him. After months of silence the hits now coming harder and faster. Our nbc News Analysis shows 8. 35 million spent on ads against trump in florida alone. Thats where the frontrunner, after winning in michigan, mississippi and hawaii, celebrated his welldone Election Night with raw trump we have the water. You have the steaks. You have the airline that i sold. I mean, whats wrong with selling . Every once in a while you can sell something. Reporter voters seem tock buying it. If trump wins in florida and ohio, hell have a clear path to the nomination. New polls show john kasich close in the buckeye state, but in florida trump is up 21 hover marco rubio who is brushing off vp talk now, struggling to show how he stays in. You are calling him a con artist. Im not running for vice president. Im not looking to be anybodys president. I want to be president of the united states. Reporter rubios regrets, his insults. Trying to outtrump trump. You know what they say about men with small hands. Something im not entirely proud of. My kids were embarrassed and if i could do it again i would do it different. Reporter hes meeting with jeb bush and ted cruz and what establishments last gasp. Cruz picking up support from a familiar face, carly fiorina, all of them looking to stop the frontrunner but looking more unlikely to do it with just six days left. Hallie jackson, nbc news, miami. Reporter this is kristen welker. Senator Bernie Sanders pulling off a stunning upset in michigan. Weve now won i guess nine states, and a lot more are yet to come. Reporter today sanders telling Andrea Mitchell its a sign he can go the distance. Reporter the polls always have us very, very far behind until election day, and then we have won state after state with huge margins. Reporter its been an unpry dictable year for pollsters. In michigan the High Percentage of independents threw off the polling. Sanders win so unexpected even he was caught off guard prompting this hastily arrange and late press event. The Political Revolution that we are talking about is strong in every part of the country. Reporter despite the upset, clinton has a substantial lead in delegates. Today the Clinton Campaign downplayed after her big win in mississippi last night, looking ahead to next weeks battleground primaries. If you work for me and if you vote for me, i will work my heart out for you. Reporter but the loss in michigan underscores vulnerability. Democratic officials expressing concern clinton was so focused on pivoting to the general election her ground game faltered and more troublesome, her message failed to resonate with working class independent and younger voters. Sanders hammered clinton for supporting past trade deals. Exit polls show sanders beating clinton on the issue of trade and that she is loss honest and trustworthy. Hopefully well have a good week next week. If we win ohio, nobody will remember it. Reporter sanders has a steep climb. He needs to win 60 of all remaining delegates to clinch the nomination, but he has the momentum and the money raking in millions from small donors. That will keep him in the race a lot longer than he might have otherwise been. Reporter according both clinton and sanders beat donald trump by double digits. Meanwhile, hours before tonights debate the rnc announced its filing a lawsuit over clintons emails, the Clinton Campaign calling that suit frivolous. Lester. Kristen, thanks, and facing so much pressure to win his home state marco rubios conversation with chuck todd for that town hall event in miami airs tonight at 8 00 eastern only on msnbc. An investigation is under way into the massive explosion that leveled several buildings in seattle and injured nine firefighters. They were on the scene before the blast, checking out reports of a natural gas leak when the worst happened. Nbcs galledy schwartz has the details. Dispatch, may day, may day, may day. Reporter a frantic call over the emergency radio after a catastrophic blast. I have firefighters missing. Reporter followed by an incredible response. All members are accounted for. I do have two injuries from flying debris. Reporter all tolled nine firefighters injured but all of them alive. Minutes earlier the firefighters had been searching for a gas leak near three businesses and now totally obliterated from a blast that sent debris and a some wave throughout the entire neighborhood. I woke up to a huge boom. I looked out the window, and my neighborhood exploded. Reporter the call originally came in at 1 00 in the morning after someone reported smelling natural gas. Firefighters responded, searching for the leak before an explosion so powerful it registered as an earthquake. The blast, caught on this store surveillance video. We know as firefighters that this is a very dangerous job. Reporter each year natural gas explosions wreak havoc n. New jersey last year an explosion leveled this home and injured 15. In 2014 another explosion in harlem killed eight and injured more than 70, and in 2010 eight were killed and entire blocks leveled in a pipeline explosion today in greenwood, the neighborhood coffee shop, a Convenience Store and a restaurant are unrecognizable in the rubble. Complete disbelief that Something Like this would happen. Reporter but entire community, even children in the playground, are giving thanks that every firefighter survived. Tonight the seattle fire chief says all of those firefighters have been released from the hospital. They are shaken up, spirits. He says all of them were completely decked out in protective gear and helmets and ultimately thats what kept them safe. Lester . Gadi schwartz, thank you. Questions are being raised after a fugitive wanted for the atemed murder of a pastor who led a prayer at a ted cruz rally was able to board a plane and fly across the country making his way all the way to the white house where he was taken down by secret service. Heres nbcs justice correspondent pete williams. Reporter the secret service searched the white house grounds today at the spot where police say an idaho man, kyle odom, tossed papers the fence last night. Hes charged with shooting a pastor outside a church in coeur dalene, idaho, sunday. The day before pastor Tim Remington gave the invocation at a ted cruz rally. A humble man that listens to god and listens to the people. Reporter police say after sundays shooting odom boarded a flight and made his way to washington despite an arrest warrant for attempted murder. A former Homeland Security official says the nofly list is not for wanted fugitives. The system was designed to prevent terrorists from getting on airplanes and protecting the Aviation System against terrorists. It was not designed to find every criminal in the criminal database or every lookout that the National Law Enforcement community is looking for. Reporter even so tsa screeners who check ids are briefed before the shifts on priority of high priority fugitives and is based on prompt notice from police which did not come in. Odom has a history of mental problems. On his Facebook Page he said the world is civilization from mars and pastor tim is one of them and in another post he said president obama is aware martials are taking control of peoples minds. As pastor remington recovers from six gunshot wounds, his family is optimistic hes probably a little afraid, but his faith is stronger than anything else in his life, so hell pull through. Reporter odom appeared briefly in court today and was ordered held without bond while idaho police seek to get him back. Pete williams, nbc news, washington. U. S. Forces in iraq have captured a chemical weapons expert for isis. Under interrogation hes reportedly revealed Key Information about isis chemical weapons and operations this. Detainee formerly worked for saddam husseins rejeempt defense Officials Say isis has already used artillery loaded with chlorine and mustard bowed ir. Thousands have begun paying their last respects to former first lady nancy reagan. She is lying in repose at her husbands in california through tomorrow. And tonight nbc news is hearing exclusively from her daughter patti davis about the legacy her mother leaves behind. Nbcs Andrea Mitchell has more. Reporter today nancy reagan began her final journey, her casket carried by her secret Service Detail past and present. Salutes as the hearse traveled the freeway, including one named for her husband, usually jammed. Today area Fire Departments paying tribute. And as the hear sze approached the Reagan Library people gathering, some with red roses, nancy reagan red. Patti davis spoke with maria shriver, also a former california fliedy. Its really comforting to see all of these people who im sure are not all republicans. Reporter right. Standing out on freeway overpasses to pay their respects. Reporter and to your hand, oh, lord, we commend our sister nancy. Lie in repose for two days as people pay their respects. Today including House Speaker paul ryan. The last years in declining health and without herrony were lonely. She told me once she was not afraid to die. She said i dont want it to hurt, but im not afraid to die. Ill see ronny again. Reporter now a threeday period of mourning. America on sunday lost a former first lady, but i lost my mother. Im happy for her that shes with my father. Reporter nancy reagan will be laid to rest friday next to herrony, finally at peace. Andrea tchell, nbc news. Still ahead tonight, con artists posing as irs agents on the phone, tricking thousands into handing over money. We even caught one of the scammers in the act. Weve got an urgent warning for you tonight. Also, we took a chance on four lads from liverpool and the world was never the same. Remembering the man beatle still ahead. There is an urgent warning from the irs and fbi about a scam that thousands have fallen for, phone calls demanding money for taxes you dont owe. Its so widespread the irs place it had on a list of socalled dirty dozen tax frauds for this year. Nbcs Olivia Sterns met with one woman who cant escape the calls. Final notice calling from the Internal Revenue service. Weve filed a lawsuit. Reporter so hes saying final notice and we have filed a lawsuit . Yes, its scary. Reporter thats the third call Gretchen Lindquist has gotten in just three weeks from someone pretending to be with the irs and demanding money. Its very upsetting, and then this morning, again, one more time, from a different phone number. I started to feel threatened by the repeat calls. Reporter luckily gretchen, an i. T. Analyst in the houston, is savvy enough to know these calls are boeingus. 900,000 people have reported getting one of these calls, and the irs estimates 5,000 have paid up. Were just scratching the surface, that this is just the tip of the ice berks and even anecdoteally knowing people in this office have gotten calls, my father has gotten calls like this. Attorney works to track down the people on the other end of the line. Last year he sent the ringleader of a massive irs Call Center Fraud to jail for 14 years. Catch these guys . Its sometimes very difficult because you have people who are not necessarily in the united states. You have Shell Companies that are being used. Reporter the irs wants you to know that it will never contact you for the first time by phone, demand credit card information or threaten arrest. Gretchen and i decided to call one of the numbers back. How can i help you . You just called my friend and threatened her with a lawsuit claiming to be a federal agency. Reporter for gretchen though its no joke. I dont even want to answer the phone. Im about to get my cellular phone number changed. Reporter now if you do get a call like this the u. S. Attorney is asking that you please hang up the phone and report it to the fbi. Can you do so on the website or by phone, but, lester, no matter what, the most important thing is please do not give your Social Security number out over the phone. How about that reaction, its a prank, unbelievable. Were back in a moment with an airline that purpose so pas tis appointing news from doctors at the Cleveland Clinic who today said the nations first uterus transplant has failed. A 26yearold woman received a transplant two weeks ago and everything appeared to be going well until she encountered complications and the uterus had to be removed. The patient is recovering, and the hospital says it will continue to try more transplants which have been successful in europe. Most of us in the u. S. Couldnt see last nights total Solar Eclipse with our own eyes, but passengers aboard one Alaska Airlines flight got the view from 37,000 feet over the pacific. About a dozen astronomers were on board to witness the very rare phenomenon. One of them got the airline to push the flight back 25 minutes so they would intercept it at the perfect time. Something they were pretty excited about all of that. When we come back, the fab finally tonight, a tribute to the man many will remember as the fifth beatle. George martin was a veteran of the royal navy with a background in Classical Music when in 1962 he met four moptopped unknowns who played rock n roll, and together they changed music and the world forever. Nbcs harry smith looks back. Reporter it was George Martin who signed the fab four to their first record contract. Please love me do reporter his Classical Music training lifted the popular bar bond into a sensation. Martin was the one who sped up the tempo of please, please turning it into a number one hit. If i please you reporter can you even imagine the accompanying spring quartet. Horns in sergeant pepper. Reporter all that accompanied the beatles musical adventures from india. Reporter to psychedelia. Lucy in the sky with diamonds reporter and if anyone deserved to be called the fifth beatle, it was George Martin, and it was he who brought the dramatic organizations to mccartneys bond theme. To live or let die reporter later on, martin helped elton john turn his candle in the wind into goodbye Englands Rose in tribute to princess diana. Because i love you, too reporter martin was the guiding hand that nourished and encouraged the Creative Forces of the beatles considerable talents. Its entirely possible had it not been for George Martin none of us would have heard of them much less worshipped the harry smith, nbc news, new york. And that will do it for us on a wednesday night. Im lester holt. For all of us at nbc news, thank you for