bridge. we'll have that at 6:00. good night. on this sunday night -- turning up the heat. as the brutal war in syria rages on, mounting pressure on the president to take stronger action against the syrian regime. the investigation. new questions about the boston bombing suspect's overseas training and whether they acted alone. out of nowhere. a fast-moving storm leads to flash flooding and fntic calls for help by those trapped in high waters. music to their ears. how itunes has changed the way we consume and experience popular culture ten years, billions of downloads and dollars later. and, best friends. both in need. a boy and his dog, an unbreakable bond. a boy and his dog, an unbreakable bond. and what brought them together.

captions paid for by nbc-universal television good evening. with the country still slowly extricating itself from the war in afghanistan and looming threats in north korea and iran, some hard questions being asked tonight about what, if anything, the u.s. can and should do militarily to end the conflict in syria. the subject has reemerged on to the front burner following indications the syrian regime may have used chemical weapons against its own people. last summer the obama administration suggested such a step would be a trigger for intervention. now the white house wants stronger evidence, even as the call grows louder in washington to act now. nbc's peter alexander has more from the white house. >> reporter: inside syria's civil war, another round of violent clashes today. at least seven rebels reported dead. just days after the u.s. said evidence suggests bashar al

assad's regime has used chemical weapons, president obama is facing growing pressure to act with republican lawmakers pushing several options. >> if you could neutralize the air advantage the syrian government has over the rebels, i think you could turn the tide of battle pretty quickly. >> a safe zone. arming the rebels. making sure we help with the refugees. i do want to give them the assistance which would give them a dramatic shift in the balance of power in syria. >> reporter: president obama has warned syria that using chemical weapons would be a game changer. >> a red line for us is we start seeing a whole bunch of chemical weapons moving around or being utilized. that would change my calculus.

that would change my equation. >> the president's laid down a line. it can't and dotted line. it can't be anything other than a red line. more than just syria, iran is paying attention to this, north korea is paying attention to this. >> reporter: in today's "washington post," anne marie slaughter, a former obama state department official insists the game has already changed and that u.s. credibility is on the line. obama must realize the tremendous damage he will do to the u.s. and to his legacy if he fails to act," she writes. but white house officials say they still have too many questions about the origin of the weapons and how they were used. this weekend syrian leaders dismissed u.s. claims that they've used chemical weapons, calling that a bare-faced lie and adding to the complexity they blame the rebels for chemical attacks. as they weigh their options, administration officials stress the need for caution. a decade after faulty intelligence contributed to the u.s. decision to invade iraq. nicholas burns is a former bush administration official and diplomat. >> we do need to learn the lessons of history before we use military force. we have to be absolutely sure of the reasons for which we use it. >> reporter: about those calls

for stronger action, lester -- republican senators said they are against sending american troops into syria. in the words of john mccain today -- that is the thing the u.s. could do right now. >> peter alexander, thank you. we turn to the boston bombing investigation. now new questions tonight about the path the suspects may have taken leading up to that violent and deadly day two weeks ago tomorrow. nbc's michelle franzen is in boston now with the very latest. michelle, good evening. >> reporter: good evening, lester. nbc news has confirmed that russian authorities in the initial days after the bombing here in boston reached out to u.s. authorities and told them back in 2011 that russian authorities had actually had a wiretapped conversation that they had recorded between tamerlan tsarnaev and his mother and a conversation where the russians say where they discussed jihad. this conversation, authorities tell us, say there is no link or connection at this time to the bombings here in boston but investigators are still tracking leads here and overseas.

a key focus for investigators centers on tamerlan's tsarnaev's visit to dagestan in 2012 and what he did during his six-month stay. authorities tell nbc news they are weighing russian reports on what they learned about tamerlan while he was visiting family. big question sunday for lawmakers, whether tamerlan received training during his trip. >> i suspect that ultimately we're going to conclude that a lot of the radicalization took place before the trip, that these brothers particularly the older brother, were more self-radicalized, online sources were among the most significant factors. >> reporter: several former counterterrorism officials tell nbc news investigators are leaning toward a theory that the two suspects did not have training and acted alone. pointing to serious flaws in the operation. the suspects had no escape plan and returned home after the bombing. police say they car jacked a vehicle and stole money from the victim.

and on the day of the bombing, authorities say they stood out an, unlike everyone else, were not in a panic. in boston this morning, at the old south church, a moving walk and vigil to the marathon finish line. healing moments for young and old alike, and signs the boston strong spirit is thriving. and all along boylston street only one business is now not open. the rest of them have opened here and the memorial back here, there is much more than just an outpouring of people and written notes. we're also learning that the one fund created to help victims has received nearly $27 million in donations. lester? >> michelle franzen tonight, thank you. another investigation. the arrest this weekend of a new suspect charged with sending ricin tainted letters to president obama, a u.s. senator and a mississippi judge. everett dutschke is set to be

arraigned tomorrow in federal court in oxford, mississippi. in texas and other parts of the south tonight, they are recovering from a destructive spring storm that led to widespread flooding and some dangerous moments for more than 100 people who got trapped in rising waters. nbc's janet schamlian has more tonight. >> reporter: it came fast in the houston area. as much as eight inches of rain in just a few hours, triggering flash flooding and turning streets into rivers. >> it was just ridiculous. waters are at least 2 1/2 feet high in the right lane. it was nuts. >> reporter: drivers were stranded all across the city. firefighters made more than 150 water rescues in five hours as cars stalled in the fast rising water. >> just coming home from work. i decided to take a chance. but me not listening, i see other cars out here. i just gave it a shot and now i'm trying to start my calm -- i

don't know what to do now. >> reporter: lightning and downed trees cut power to more than 40,000 customers. and in the south, something rare -- hail. >> on the ground is hail! >> reporter: in parts of tennessee the weekend was a washout. heavy rains pushed creeks over their banks, spilling on to nearby roads. as storms move out of tennessee and texas, the focus moves north. >> the big story this week is going to be watching the battle of the red river rising and how the communities of fargo, north dakota and morehead, minnesota deal with those rising waters. >> reporter: fargo hopes the more than million and a half sandbags are enough. ahead of tuesday's expected crest. janet schamlian, nbc news, houston. here in the northeast, it was six months ago tomorrow that hurricane sandy swept through the region. battering the landscape and countless lives. since the storm more than half million people have registered for assistance from the federal government. nbc's stephanie gosk is in seaside heights on the jersey shore tonight with an update for us. stephanie. >> reporter: good evening,

lester. i'm standing in the middle of what will be the new boardwalk for seaside heights. mayor tells us that it will be ready and open before memorial day but that can't be said for the rest of the jersey shore where progress is definitely mixed. there are homes along the jersey shore that look like they haven't been touched since sandy hit. a beach house swept into the bay by the storm still sits there. last november, we saw homeowners making an emotional return to the beach. >> it is devastating. devastating. i don't know what else to say. >> reporter: today, there was virtually no one there and it looked exactly the same. lack of money and battles with insurance companies are slowing down the recovery. >> there was a fence here -- >> reporter: ruth, a full-time resident, lives a little further south where work is being done, but it is slow going. >> at first everybody was yeah, yeah, rebuild. but i think now everybody's just tired. we're just exhausted. >> reporter: but on a warm

sunday in april, there is a hint of what summer normally promises, and some brisk business at bakin' bagels, reopened just a couple of weeks ago. you guys make a good bagel? >> a great bagel! >> reporter: carol barr is one of the tens of thousands of people in new jersey and new york who are still displaced. her house destroyed, she's renting the apartment above the shop. >> 98% of my street, the houses are gutted. we're not doing anything yet. very sad. >> reporter: after almost complete devastation, progress is measured one board at a time, especially in seaside heights. >> so many people depend on this boardwalk. >> reporter: for the mayor, rebuilding the boardwalk quickly wasn't just good business. >> we're putting this back together again for all the people that have been here, have all those wonderful memories of coming here and all those new memories that are going to be formed. >> reporter: restore the shore is a mantra heard everywhere.

scott designed the t-shirts donating $500,000 from his sales to help rebuild. nobody's just going to give up now. we see the challenge but they're getting through it and we'll be open for the summer. >> reporter: the roller coaster here at seaside heights has been a symbol of sandy's destruction from the very beginning. but when the weather conditions are right, construction workers are going to tear it down and cart it out of here. right now it is a health hazard and the priority is getting this beach open for the summer. lester? >> stephanie gosk on the jersey shore. stephanie, we want to remind folks, brian williams will have much more on sandy six months later tomorrow right here on "nbc nightly news." there's hope and heartbreak tonight at the scene of that deadly building collapse in bangladesh where 377 people have died. today sparks from equipment caused a fire at the site complicating efforts to find the hundreds still missing. also today authorities said the owner of the building was captured as he tried to escape

into india. in rome, violence as italy's new coalition government was sworn in today. authorities say a man shot and wounded two police officers outside the new prime minister's office. the man reportedly told police he was protesting politicians who have let italy's economy languish for the past 20 years. when "nbc nightly news" continues on this sunday, how the injured in boston will benefit from advances that have changed the lives of america's wounded warriors. and, the inspirational story of a warrior puppy whose unconditional love has touched a little boy.

in the aftermath of the boston marathon bombings, doctors were forced to perform amputations on at least 14 patients. many of them are already finding a ready support network among

veterans of the past two wars where hidden explosives have taken a devastating toll. wounded warriors who can tell the boston survivors a lot about hope and living a full life. it was not what anyone expected on the streets of america. instantly the fates of ordinary americans horribly maimed by improvised bombs were inextricably linked to wounded american soldiers like calvin todd. >> we were on a mission, foot patrol. >> reporter: todd's life altering moment happened in afghanistan. >> i stepped on a secondary and lost my lower left leg. >> reporter: now the 26-year-old is on the front lines of a different kind. >> i'm almost back to new. i can run eight-minute miles new. i probably got four or five different feet for different activities. >> reporter: todd is one of nearly 1,600 service members to lose limbs in combat since the

start of the war in afghanistan. for many the road to recovery is through here, walter reed medical center in bethesda. doctors say the painful experiences of the battlefield have changed the future for all amputees. >> we have plenty of example of that from our injured service members who have thrived from the extraordinary blast injures. there's no reason to think the victims in boston won't do the same. e, born of decades of war, ning have produced advances in bionic hands, knees, ankles, and beyond. >> i can rotate all the way around. >> reporter: travis mills is 1 of 5 quadruple amputees from both wars. >> i'm very fortunate that the research that has been done has benefited myself through my injuries. i know if i would have got hurt like i did ten years ago i probably wouldn't have made it off the battlefield. >> reporter: there are new approaches to rehabilitation, too, physically and mentally. >> they need to have a good perspective who they are, they

have to feel good about themselves. >> know that you just keep moving forward, keep going and we'll get better. >> reporter: calvin only needs to look to his side for inspiration. while the landscape in afghanistan is a long way from boylston street, this war veteran knows what the boston victims have to overcome and what they have to look forward to. >> to get out of bed and start moving, it is going to come back to you quick. there is a lot you can do. the sky's the limit. you can do anything you want to do. just work for it. >> it is important to note some of these incredible advancements in technology can cost tens of thousands of dollars. and while it is uncertain what their insurance providers will cover, the marathon bombing victims will surely have options that would not have been available just a few years ago. a passing of note tonight. you may not know the name alan wood. he plays a small but unique role in win of -- one of the biggest battles of world war ii. in 1945 wood was a young navy

officer that provided the american flag that was raised on the pacific island of iwo jima. after a brutal battle with the japanese. the photo became one of the iconic pictures from the war. alan wood was 90 years old. when we come back, a milestone in pop culture. tenth anniversary of itunes. ♪

that's "i got a feeling" by the black eyed peas. the top selling song in the history of itunes. ten years after apple started a digital download revolution, itunes has brought major changes in the way we consume music, movies and books. here's nbc's mike taibbi. >> reporter: it was a revolution. a coup. a takeover. out with the old, in with itunes. is there itunes reshape our lives. it completely changed what it meant to buy music. >> there it is, right there. >> reporter: it was ten years ago today that apple's steve jobs opened the itunes store, 200,000 songs at 99 cents a piece.

the whole album only if you wanted to pay for it. the hot song in the beginning, u2's "stuck in the moment." by year's end, a swooning public downloaded 25 million songs. in '05 they could buy tv shows, in '06 movies. >> the technology keeps moving and lets us do more and more. >> reporter: when jobs unleashed his iphone in '07, all that content could suddenly go wherever you were going and revolution had fully flowered. >> itunes has changed our culture because it gives us everything now. >> reporter: it was a digital world realized and delivered. >> i can pick and choose what i want and do it any time. it is totally convenient. >> i download at least an album or more songs every week. >> reporter: even for the millions who still have one of these or these or these and can't bear to toss all that vinyl, those movies on vhs, the move to the new wave has been almost irresistible. in 2012 itune's total sales now including apps and ebooks,

topped $4 billion with 35 million songs, 60,000 movies and approaching 2 million books available worldwide. the obvious question -- what next? >> it may change that internet radio streaming market when it gets there the way that it changed the whole music market when it opened up ten years ago. >> in the meantime, anyone know where you can get this two-inch tape converted? i know. that was then. this unquestionably is now. mike taibbi, nbc, los angeles. a word about last night. they held the annual white house correspondents dinner in washington where the worlds of politics, news and entertainment come together and sometimes collide and where the president, as are you about to see, gets to let his hair down. >> i understand second term, you need a burst of new energy. try some new things. and my team and i talked about it. we were willing to try anything. so we borrowed one of michelle's tricks.

i know republicans are still sorting out what happened in 2012 but one thing they all agree on is they need to do a better job reaching out to minorities. and look, call me self-centered, but i can think of one minority they could start with. some folks still don't think i spend enough time with congress. "why don't you get a drink with mitch mcconnell," they ask. really? why don't you get a drink with mitch mcconnell? >> the president as comic in chief last night in washington. up next here tonight, the remarkable thing that happened when a boy in need found a new friend. ♪ you've got a friend yeah

i think you are going to look our final story. all of us did. about two friends, dedicated and devoted to each other, but each with their own special needs. nbc's jill rappaport on how they came to each other's rescue. >> zechlt. zena, good girl. >> reporter: they call her zena the warrior puppy. a title this abused and abandoned dog earned because of her miraculous story of survival. >> that's zena! >> i've never seen a puppy anywhere near the condition she was in. >> less than 1% chance of survival.

>> it wasn't good. >> reporter: but against all odds, this little puppy that could did and on her road to recovery captured the hearts of thousands. including linda and grant hickey who ended up adopting her. >> good girl! i just fell in love with her off her facebook. yummy! >> reporter: but little did they know that the survivor would end up becoming a savior. for their 8-year-old son, johnny, who has autism. >> the relationship between them is unlike anything i can describe. he had issues with -- you know, social issues having autism. and she breaks that barrier for him. they are best friends. johnny talks to her. johnny sings to her. it is really remarkable that what this dog has done for johnny. >> most kids with autism really want to socially connect. they're really socially motivated and interested but

they lack the skills to do so. sometimes a therapy dog can be a really amazing tool in order for foster social relationships. >> how do you explain the gift that this animal has brought to your family? >> you know what? i don't even know if i can explain it in words. it is just so heart warming to see it. i believe god has a plan, you know? and on february 11th a dog walked into my home. a dog walked into my home and made the difference. >> reporter: jill rappaport, nbc news, johns creek, georgia. >> like they were meant for each other. that's "nbc nightly news" for this sunday. brian williams will be here tomorrow. i'm lester holt reporting from new york. for all of us here at "nbc nightly news," good night. i knew there were a lot of tech jobs available out there.

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