it sounded like sandra. >> it was mumbling. >> where was her voice coming from, marissa? >> we did not know. my dad -- i just remember he just ran straight into the master bedroom. >> reporter: marissa raced after her father. >> i just hear, saying "help. someone's in trouble." >> are you really scared at this point? >> yes, i was scared. >> reporter: the voice was coming from inside a walk-in-closet attached to the bathroom. herman moved closer. wedged against the door knob was a dining chair. he tugged it aside, opened the door, and there was sandra -- on the floor, tied by her arms and ankles, but alive. >> he said that she did not look well at all. >> reporter: as marissa's mom cut sandra loose, her dad spoke. >> "where's my brother? where's your uncle?" >> reporter: the answer to that, unspeakable. s is wh >> >> coming up -- >> she looked like she had aged ten years overnight. >> just broken and lost. >> sandra melgar, the only possible witness to a night of terror. what would she remember? when "dateline" continues. ciate, and all of you doing your part - at home. ♪

that was marissa perlman reporting. safely responded saying they continue to enforce social distancing at the social distribution center. employees are not required to take breaks and lunches separately. they are also requiring employees to take masks. >>> a warning from law enforcement about scammers who prey on our fears as we shelter in place. they warn criminals are trying to get banking information using several different strategies. some of the offers making the rounds, home coronavirus test kits, cures for coronavirus and fundraisers for victims of the disease. >>do not be giving out your personal information, do not be providing people with u havenot initiated it. a lot of unscrupulous people are, unfortunately, exploiting this situation to commit crimes. >>police say to be careful about fake emails with links that can infect your computer with malware. if you want to donate, they suggest checking the source first. >> a cannabis company in san jose is making a donation to workers fighting on the front lines. vol

>>ter: a ne c different way of life, putting on masks, inour hands, hunkering down, consider marissa. in the comfort of her own home, miller is a newly minted citizen scientist, all thanks to a smartphone and a special app. >> here is the app icon. it's a little heart. >> reporter: it's called the covid-19 citizen science initiative. >> so far it's been really interesting, and i file a little proud that i'm participating in the cause. >> reporter: the goal? to advance the understanding of how and where the virus spreads, and why it's lethal in some people, but not others. the hope? that it goes viral in a good way. >> we're hoping every participant shares it with five of their friends who will then share it with five of their friends and so on. >> we like to show contac among aln hespcien and sprea tionm. hehow p. there's initial survey of your health and daily habits. you the option of sharing your location and other data, such as step counts. >> and they pop up in the morning and just let me know it's time to check in. >> reporter: participants answer surveys, some daily. >> we ask

. >> i'm hesitant about going back to work because of what's happened >> reporter: marissa cabello testeditive after working at a grocery store in irving, texas. the county now offering covid-19 testing to all essential employees. but there are calls to go further some unions believe grocery stores should close their doors to the public only allowing pickup and delivery service as hundreds of employees at amazon prepare for another walk out this week to demand better protection several food processing plants across the country are struggling to keep workers safe morgan chesky is in waterloo, iowa >> officials say 90% of new cases here can be traced to this tyson meat processing plant. the company says it's added safety measures such as temperature scans but tonight isn't sharing number of positive cases nor is it closing. >> reporter: tonight worker safety and small businesses attacking americans and the economy. migle almaguer, nbc news >>> we're back in 60 seconds with the deepening mystery over the health of kim jong-un. >>> plus an amazing turn around for a coronavirus patient once in

marissa levine is a professor of public health and critical of patchwork policies. >> we need a unifiedsage. yo need it more than ever now. >> reporter: so you would like to see something beyond the state-by-state, and county-by- county measure. >> let's just say it wouldn't hurt. her parents gloria and bill weed are passengers on the cruise ship "zaandam" which is stuck at sea. four passengers have died and many covid-19 cases are expected. >> my dad has developed pneumonia, and he's getting worse every day. >> reporter: do you think it's covid-19? >> it probably is. >> reporter: but the ship has not been given permission to disembark at its final destination near fort lauderdale. >> i'm afraid if it takes too long to get to florida and get to a port that it might be too late for some of the passengers. >> reporter: the governor has said he would allow floridians to disembark but that he does not want foreign nationals on that ship to take up limited tespital beds in the state. norah. >> o'donnell: all right, manny, thank you. now to an update on the "uss theodore roosevelt." nearly 10

marissa asks, which homeless individuals should be placed in housing? are you prioritizing them on whether they are infected, could be infected, elderly, medical? >> as i stated a few times, fema has specific guidelines as it relates to project room key. we are doing all kinds of other work at the local, regional, and state level on the issue of homelessness broadly defined. this is a subset of that work. specific subset requires three things. one, if you are covid positive, that is in isolation responsibility and an opportunity in this new partnership. second, if you have been exposed -- forvirus meaning you example, if you are in a shelter and individual has been there who may have been spreading but theretimately identified, is a likelihood others may be infected or a staff member was infected. that is someone who has likely been exposed and we are trying to get them out of a congregate facility into a more isolated setting which is the second point of appropriation. point for the appropriation. third, high risk is defined many different ways. but pe

marissa levine, a professor of public health and family medicine at the yurcuniversity of south flo in tampa. dr. levine, can you hear me? fwl i can hear you. good morning. >> thank you so much for getting on the phone. i really appreciate it. we heard from rosa said right there, that the governor in florida is facing a lot of criticism for not doing more. you take issue with the governor's position on this here as well. what is your message to him? >> so i understand what the governor is trying to do. he's trying to use data to make good policy decisions. our problem is that the testing has been delayed, and so the testing doesn't really give a full picture of what's going on in florida. i'm worried that people might be misled by the testing that in areas where we haven't had a case or maybe very few cases there might be the conclusion there's been no spread of virus, but we don't really know that, and we also know that doing these efforts, the physical distancing early, makes a big difference. and you know, i think that we're add a time where those decisions have to be made. >> yeah,

>> it's a really interesting challenge marissa. it difficult to know the will result in a shuffling of feet of 40s or responsibilities between states and the federal government. but i do think it will have long-term consequences in reminding us that governors have to be good chief executives in a way very many national politicians don't have to. running a senate staff isn't necessarily the best preparation for running the federal government but running a state of the mecca to the california or washington state or ohio where you have to balance your budget every year and also on health care. it's one taxpayer's view but it does seem to be likely that it's going to remind us why so many governors have been effective presidents. >> james he mentioned before we were talking about trump's approval rating and they want to shift their discussion looking forward to november because obviously the cornerstone of our democracy is a free and fair election. what happened is even in the times we have risen above the noise can you just tell me yo

adjust to a different way of life, putting on masks, washing our hands, hunkering down, consider marissa miller of tiburon in the comfort of her own home miller is a newly minted citizen scientist all thanks to a smart phone and a special app. >> here is the app icon. it is a little heart. >> reporter: it is called the covid-19 citizens science initiative. >> it has been interesting and i feel proud that i'm, you know, participating in the cause. >> reporter: the goal, to advance the understanding of how and where the virus spreads. and why it is lethal in some people and not others. the hope that it goes viral in a good way. >> they're hoping that every participant shares it with five of their friends and shares it with five of their friends and so on. >> we like to show how contact among individuals can spread science and solutions. >> reporter: download the app and there is an initial survey of your health and darely habits. you have the option of sharing your location and other data such as step counts. >> they pop up in the morning and let me know it is time to check in. >> reporter

>> gracia and marissa. >> hello, girls. are you sisters or are you friends?sister. >> you're sisters. and have you been busy as well this morning? >> yes. >> what have you been doing? oh, look at that. >> your flowers, they're brilliant! >> wow, that's brilliant. >> is that a little handbag? >> no! >> it's an easter bag. >> sorry. it looked like a little handbag. >> that is so cute. the royal couple paid a virtual visit to students and staff at school in northwest england this morning. the children showed off their drawings and their bunny ears. england has kept some schools open for the children of essential workers. >> that's adorable. >> yeah, it's so cute. >> they did a great job. let's turn our attention to the weekend weather forecast. easter is here. spencer back. >> and warmth is coming back as well. here is a look at what's going on. right now these are forecast features. we'll see a chance of isolated showers overnight. mainly in the south bay. sunny and warmer for easter weekend, as dan just mentioned. and the warm willing continue and increase int

marissa: i just hear her saying, help, someone's in trouble. i was scared. i was scared.

. >> marissa martinez teaches at harvey milk civil rights academy in san francisco. >> hi, boys and girls. it's miss martinez. how you? >> like hundreds of teachers in that school district, she has been communicating with their students on the internet. her 11-year-old daughter records all of her lessons and estrella makes a number of cameo appearances. the lessons are posted on her youtube channel. she also zooms with her kindergartners. >> i realize there is technology out there.crazy. >> the classroom chicken and the tortoise came with her once the schools were shut down. >> everyone say hi to mr. narwhal. >> nice to see you, hope you're doing good. i hope you read about my cousin, big blue. >> today's lesson is of course about whales. she also expects students to do homework. >> and i want you to give me two or threences about facts about the big blue whale. >> when she was done, i asked her how she was holding up. you must be exhausted. >> i am. it's -- it's a fine line of insanity, let me tell you that much. i don't pay my baby-sitter during the day enough money i believe now. i've

our first prize middle school over toward those two marissa boucher, yuna chun, and defne ustundag, eighth-graders from silver spring, maryland. their winning entry is entitled "blackout," misinformation in the age of social media. >> the president, accused of

our first prize middle school over toward those two marissa boucher, yuna chun, and defne ustundag, eighth-graders from silver spring, maryland. their winning entry is entitled "blackout," misinformation in the age of social media. >> the president, accused of abusing his power. [indiscernible] [typing] >> social media. hundreds of platforms, millions of users, and a growing influence on today's society. since its beginning, social media as a platform for online journalism and the continued development has allowed for the growth of thousands of different communities. fandom's and sports teams, support hotlines, it has helped the world connect in ways previously unimaginable. that there is a downside to all of this connection. as more and more people gave the ability -- gaming ability to say what they want on social media, they also gain the ability to spread misinformation. has furthered the liberty of the free press, but because of the use of confirmation bias, promotion of eight, and influence on the 2020 election, it should be addressed by candidates as an important influence on public opinion.