from nbc news world headquarters in new york this is "nbc nightly news." reporting tonight lester holt. good evening. few things have rattled the world quite like the prospect of iran developing a nuclear weapon which is why all eyes this week have been glued on a small city in switzerland where today nearly around the clock negotiations with iran and how to curb its nuclear program finally produced the framework of a deal. one that president obama quickly proclaimed would ensure iran will never be able to develop a bomb. but then there's the issue of what iran gets in return and whether any deal will hold. our team has it covered. we begin with andrea mitchell in lausanne. andrea. >> reporter: good evening, lester. it's been 18 months of tough negotiations ending with an all-nighter that still left several key issues unresolved. but tonight the united states could be entering a new era in its relationship with iran. and president obama is telling critics this will make our world safer. after marathon talks a agr far more specific than many had expected. the weary negotiators set off to sell it back home as president obama launched what will be a tough campaign. >> if iran cheats the world will know it. if we see something suspicious we will inspect it. iran's past efforts to weaponize its program will be addressed. >> reporter: it requires iran not to enrich uranium to weapons grade for 15 years. to reduce its number of operating nuclear centrifuges from 19,000 to just over 5,000. to increase the time it would take to make a bomb from a few months to a year. and to convert its underground plutonium reactor ta peaceful research. u.n. inspectors will have full access to all of iran's nuclear facilities. and iran gets relief from sanctions only it e if it meets its commitments. iran's foreign minister javad zarif. >> there will be no sanctions against the islamic republic of iran. >> reporter: they couldn't agree on when they would be lifted. and a fact sheet tweeting there is no need to spin using fact sheets to early on. zarif and kerry also couldn't agree on a joint statement. if you couldn't agree standing up and announcing together exactly what you've agreed on here what would you think that in the next three months you're going to actually come to an agreement? >> because there's a great deal of difference for them between what happens now and where this goes and what can happen when you have a final signature. >> reporter: you think you can get a deal by june? >> i'm not promising anything. no is the president. what we've done is open up the opportunity. >> reporter: but first they'll have to persuade congress and iran's skeptical neighbors. andrea mitchell nbc news lausanne. >> reporter: this is ann curry. the u.s. and iran are trumpeting today's deal but others are deeply skeptical. israel called it a historic mistake. prime minister netanyahu tweeting any deal must significantly roll back iran's nuclear capabilities and stop its terrorism and aggression. and israel has surprising company. much of the arab world agrees iran with its regional and nuclear ambitions cannot be trusted. that includes another u.s. ally saudi arabia. >> everybody wants a good deal that prevents iran from developing an atomic bomb. >> reporter: but the agreement was welcomed by many in iran. desperate to get out from years of crippling economic sanctions. nbc's in tehran. >> when the news of the deal reached tehran, some people took to their cars and went to the main squares in the city honking their horns and slashing signs celebrating the news. >> reporter: iran's foreign minister speaking this evening after days of marathon negotiations fought again to reassure skeptics that iran's nuclear ambitions are strictly peaceful. >> we have decided to take steps for a period of time to assure anybody who had concern our program is exclusively peaceful has always been and will always remain exclusively peaceful. >> reporter: and iran's foreign minister and his team are expected to be greeted with a hero's welcome when they return home tomorrow lester. >> ann curry tonight. thank you, ann. another major story we're covering tonight, a massacre on a college campus in kenya. terrorists launched a horrifying attack that went on for hours. when it was over at least 147 people were dead. many injured. and a warning, some of these images are frankly quite hard to watch. our chief foreign correspondent richard engel has our report. >> reporter: the attack began before dawn. witnesses say masked gunmen entered the campus through the dormitory. students awoke to gunfire. [ gunfire ] most of the injured were students. so were the dead. survivors say the attackers separated christians from muslims. christians were shot muslims freed. a student says he escaped by jumping out a window. but hundreds of others were still trapped inside. >> for hours we could hear gunshots and explosions. >> reporter: garissa university college is in the northeast of kenya not far from the border with somalia. it took two hours for kenyan reinforcements to arrive. u.s. counterterrorism officials tell nbc news that once the kenyans did arrive they were decisive moving in and fighting. kenya's president took to the air waves to try to calm his nation. >> we continue to pray for a quick recovery of the injured. >> reporter: the somalia-based terror group al shabaab claimed responsibility almost immediately. the militant group carried out a very similar attack on a kenyan shopping mall in 2013. then like today, with four gunmen. >> you have now competing terror groups in the world, so they have to show that they're relevant and they have to attack on a larger scale. >> reporter: the kenyan government accused this man, mohamed kuno also known by other names. leader of elite al shabaab unit. this may be the deadliest attack on a university ever. it appears to have been long-planned. over a week ago another kenyan university warned its students that al shabaab was plotting an attack. officials just didn't know where. lester. >> richard engel, thanks. a lot of fast moving developments tonight in the investigation into the co-pilot who officials say may have deliberately crashed that plane into the side of a mountain. disturbing internet searches found on his tablet computer as recovery crews discover the second black box at the crash scene. nbc's katy tur with that report. >> reporter: today, in the french alps among the scattered debris recovery workers say they've collected 40 smashed cell phones larger pieces of wreckage and, finally, in a ravine the normally orange flight data recorder looking so badly burned it was black. still investigators say they are hopeful the data remains in tact. inside the germanwings flight 9525 second black box french investigator to learn what co-pilot andreas lubitz was doing when he was alone in the cockpit. and whether just before the plane began its steep descent the autopilot had been manually changed from 38,000 feet to 100 feet as the tracking site flightradar24.com suggested last week. meanwhile in lubitz's dusseldorf apartment, german investigators hope to learn more about who he was and why he would allegedly crash the plane. and today they released some of what they found on lubitz's tablet computer. the user name the personal correspondence and the entered search words carry the conclusion that the device was used by the co-pilot said the prosecutor. from march 16 to march 23 the week leading up to the crash, he says lubitz studied medical treatments, various ways and possible methods of committing suicide and that he spent several minutes on cockpit doors and their security measures. german officials say they're going to look into cockpit security measures to see if they went a little too far after 9/11. they're also going to look into medical and psychological testing requirements for pilots to see where they can improve. katy tur, nbc news germany. here in new york two women are under arrest aed of conspireing to commit a terrorist attack in the u.s. investigators believe they were inspired in part by isis. the feds say one of them had propane tanks and instructions to turn them into bombs. but one official adds there was no specific plot. under mounting pressure lawmakers in both indiana and arkansas move late today to change their state's religious freedom laws which critics have labeled anti-gay. nbc's gabe gutierrez explains. >> reporter: today, indiana republican lawmakers announced an unlikely compromise. >> religious rights and individual rights can co-exist in harmony together. >> reporter: the agreement follows intense national backlash when indiana passed a religious freedom law. the new language spells out the law does not authorize a provider to refuse to offer or provide services on the basis of sexual orientation or gender identity. >> why wasn't this language included in the first place? >> well honestly the language wasn't needed to clarify the statute legally. it is needed to clarify it -- the perception of it. and we fixed it. >> reporter: did you misinterpret the bill? >> absolutely not. >> reporter: lobbyist eric miller. >> you going to jeopardize the freedom for a christian businessman or another faith to be forced into doing something against their religious beliefs. >> reporter: late today arkansas's governor signed a revised version of that state's religious freedom bill. >> this bill is bipartisan. it has received overwhelming support in both houses. it protects religious freedom. >> reporter: so did indiana's governor as the spotlight shifts to this weekend's final four. gabe gutierrez, nbc news indianapolis. in february as movie goers were flocking to see "american sniper" in theaters the parents of the real chris kyle were in a texas courtroom watching the man who killed their son stand trial. now for the first time since the trial kyle's father is speaking out. i sat down with wayne kyle to talk about all that's happened. how are you and debbie doing? i mean there's this movie and this book and all this but we're talking about your son. how are you guys doing? >> surviving. it's been the toughest two-plus years of our life. >> reporter: what was it like to sit in the courtroom with him? >> it was horrible. i mean gut wrenching. it's just one of those deals that you just want to jump over that railing and kill him with your bare hands. >> reporter: chris kyle left the navy in 2009. when we spoke three years ago, he told me he found purpose in helping other struggling vets. >> i want to try to figure out everything i can do possibly to help those guys. >> reporter: wayne kyle worried about his son. >> lester i told him one time i said son, i worry more about you as a civilian than when you were with the teams. he said why is that. i said because you were fully trained, highly skilled in what you did. but i said there's no training to be a civilian. >> reporter: in 2013 kyle and his close friend chad littlefield were murdered on a texas gun range by eddie ray routh, a struggling vet they were trying to help. >> we the jury find the defendant, eddie ray routh, guilty. >> reporter: it was the "american sniper" trial. >> that was so so wrong. i don't know how every branch of the media portrayed it. >> reporter: i said the words. i've bought into it. it was the "american sniper" trial. >> we resent that because it was just then about the loss of chris. the loss of chris was no more of a tragedy than loss of chad littlefield. on the heals of the film's success and trial, a texas congressman introduced a bill to posthumousl honor kyle. >> he never saw himself as a hero. >> reporter: the kyles honor their son through a foundation that supports veterans causes. they are moved by the tributes of strangers for their son and happy to have the trial behind them. >> we never had any peace to try to grieve, i guess, ourselves. but once they came back with that guilty verdict, it was like okay that chapter is closed. and there was a sense of relief. >> in february the man who killed kyle and chad littlefield was sentenced to life in prison without parole. still ahead for us here tonight, the loss of a legendary figure on television. also tornado and severe thunderstorm warnings. the threat across a huge part of the country again. al roker will join us in a moment. and later, saying good-bye to the '60s. we're onset among the last cameras there with the cast and ♪ is it the insightful strategies and analytical capabilities that make edward jones one of the biggest financial services firms in the country? 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>> we certainly are, lester. on into tomorrow. an area stretches from pittsburgh into nashville where the storms are really just starting to get warmed up. we're watching this activity push on through. and as it does we're going to watch these systems push in and start to fire up. we expect to see strong storms. we already have a severe thunderstorm watch out for jackson all the way to nashville. we're watching that. ahead of this system we've got warm moist air pushing in. and then behind it we've got colder air. and between those two that's where we're looking at the strong storms for tonight. we also expect to see heavy thunderstorms firing up. the enhanced risk stretching from springfield all the way to paducah overnight on into tomorrow it makes its way from nashville, jackson on into parts of the appalachians. heavy rain will be falling, lester. we have flash flood watches in effect. some areas picking up three to five inches of rain before it's all over. >> all right, al. thanks. we'll see you in the morning. the worst rainfall in decades has created epic flooding in chille sweeping in some cases entire towns off the map. 24 people are reported dead. dozens others missing. we're back in a moment to remember a sunday dinners at my house... it's a full day for me, and i love it. but when i started having back pain my sister had to come help. i don't like asking for help. i took tylenol but i had to take six pills to get through the day. so my daughter brought over some aleve. it's just two pills, all day! and now, i'm back! aleve. two pills. all day strong, all day long. and for a good night's rest, try aleve pm for a better am. sometimes the present looked bright. sometimes romantic. there were tears in my eyes. and tears in my eyes. and so many little things that we learned were really the biggest things. through it all, we saved and had a retirement plan. and someone who listened and helped us along the way. because we always knew that someday the future would be the present. every someday needs a plan. talk with us about your retirement today. when eating healthy and drinking water just isn't enough to ease my constipation i trust dulcolax tablets. i take dulcolax for dependable overnight relief and in the morning i am back to myself dulcolax, designed for dependable relief if you have medicare part d, walgreens gets that you might be at the corner of "looking for a good deal" and "sheesh, i wish i'd looked some more." that's why walgreens makes it easy to switch your prescriptions and save money. just stop by. and leave all the legwork to us. switch your prescriptions to walgreens where you could save even more on medicare part d with copays as low as zero dollars. at the corner of happy and healthy. apples fall, but the apples of your cheeks don't have to. defy gravity. juvéderm voluma® is the only fda-approved injectable gel to instantly add volume to your cheek area. as you age, cheeks can lose volume. voluma adds volume creating contour and lift for a more youthful profile. for up to two years. temporary side effects include tenderness, swelling, firmness lumps, bumps, bruising, pain redness, discoloration and itching. ask your doctor. juvéderm voluma®. defy gravity. the reverend robert schuller has died. the famed evangelist from southern california passed away at age 88 after a battle with cancer. here's nbc's miguel almaguer. >> let's rejoice and be glad. >> reporter: from his california pulpit a global audience of 30 million. >> good morning. >> reporter: the reverend robert h.schuller was best known for the hour of power, influenced the generation of meg church pastors. presidents came to worship, but it didn't start that way. when he was 4, guidance from his uncles. >> he put his hand on my head and said robert you're going to be a preacher when you grow up. and i said oh really? 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>> reporter: writer introduced viewers to the glossy world of a new york city ad agency. >> i heard right away from people. a really strong identification with a lot of the characters no matter how flawed they were. >> reporter: john hamm was an unknown when the show began. seven seasons took his character don draper from 1960 to 1969. >> armstrong is on the moon. >> reporter: fans obsessed over the show's meticulous detail from the dresser to the period stove in pete campbell's kitchen. and the lady bug wallpaper. we got to visit the set before shooting wrapped. >> if you opened up any of these folders, there's actual expense reports. >> reporter: for the actors nearing the end of a show that launched their careers is bittersweet. >> i know that i will see these people again. but i will never see peggy again. and i will never see don again. and i will never see joan. and i will never see pete. and that to me is the sad part. that's what gets me. >> reporter: they bonded between scenes in this oasis they called base camp. we got a rare peek. >> people are texting you got to come down we're playing catch phrase right now. >> i never had that on a show ever. people want to just hang out. >> reporter: why do you think "mad men" has done for television? >> that's for other people to say. that is really for other people to say. i hope it's had an affect on tv in the sense that it doesn't have any guns and it's a pretty small story and we managed to squeeze 92 hours of drama out of something that is pretty much i mean don's life is more exciting than yours and mine but pretty much drivederived -- >> way. series would d for about four years, but in true "mad men" fashion nobody's revealing secrets. it's an important part and i hope it effects the audience as much as it effects us. >> reporter: kate snow nbc news, new york. >> and that will do it for us on this thursday night. i'm lester holt. for all of us at nbc news thank you for watching and good . a mega celebration of paul walker as the stars of furious 7 take over hollywood. >> the moment that brought vin diesel to tears, now on "extra." diesel. >> oh! >> johnson. >> daddy's got go to work. >> statham. >> here comes the bad guy this the movie. >> mario in the furious 7 mania. vin's emotional tribute to paul. >> last year it was hard to come back to work. >> the stories you never heard. >> it true that you were hooking up with the same girl. >> harvey weinstein accused of groping this model. >> a sting with the officials. >> joe giudice talks about life without theresa. >> i cry every time i leave. >> mark barnett and rooma downey giving us a sneak peek with their mini series about jesus. >> it could be called "house of cards" ad. >> plus katy perry's extreme hair makeover. >> charissa is about to do it, too. >> can i get an amen. >> now, on "extra," f