captioning sponsored by wnet >> sreenivasan: on this edition for sunday, april 19th: the italian coast guard searches for survivors after a fishing boat packed with hundreds of migrants capsizes in the mediterranean. american military trainers arrive in ukraine, prompting an angry response from the kremlin. a scandal at the f.b.i. forensic investigators routinely exaggerated the evidence they had against defendants, including several already put to death. and in our signature segment, hackers seizing personal data and holding it for ransom. next on pbs newshour weekend. >> pbs newshour weekend is made possible by:

corporate funding is provided by mutual of america-- designing customized individual and group retirement products. that's why we are your retirement company. additional support is provided by: and by the corporation for public broadcasting and by contributions to your pbs station from viewers like you. thank you. from the tisch wnet studios in lincoln center in new york, hari sreenivasan. this is pbs newshour weekend. >> sreenivasan: good evening. thanks for joining us. members of italy's coast guard are searching for survivors after a fishing boat crowded with migrants overturned today. as many as 700 people are feared dead. the accident happened in the mediterranean, off the coast of libya. the victims were trying to get from there to italy. late today, italy's cabinet met

in emergency session. since the beginning of the year an estimated 1,500 people have died making the crossing to italy. in libya today, another atrocity linked to isis. the muslim extremist group released a video online showing the beheading of 15 ethiopian christians and the shooting of 15 others it had captured. isis called the victims" crusaders." mixed signals from iran today. that country's supreme leader, ayatollah ali khamenei said the united states had created a" myth" about his country trying to develop a nuclear weapon. meanwhile, the deputy commander of iran's islamic revolutionary guard said iran would not allow inspections of military sites, calling the idea "a national humiliation." last week, defense secretary ash carter said any final deal must include those inspections. during a television interview today, the chairman of the senate foreign relations committee insisted that economic sanctions against iran be phased out, not eliminated immediately if a final deal is reached. >> i thinks it's very important that the phase, the sanctions be phased, so that we see how iran is behaving and whether they're

actually living up to the arrangement. one of the biggest concerns people have is that iran today has the ability through covert action to do anything that they wish. >> sreenivasan: turning now to europe: about 300 american military trainers have arrived in ukraine, prompting an angry response from the kremlin. for more about this, we are joined now via skype from moscow by andrew roth. he has reported the story for the new york times. so what are the american advisors doing on the ground? >> hi hari. the american advisor who came from in the hudson 73rd airborne based if italy and they come to train ukraine's fat guard b a thousand members of the national guard are engaged in in combat in the east of the country an they're going to be working on what they said were military training as well as specifically focusing on the officer corps. so this is a very new unit that the national guard so the officers a lot of them

haven't had much training yet at all. >> srennivasan: so this is short of supplying any arms or weapons to the ukraine. the united states has refused to do that right? >> so far they have. the united states has supplied somewhat is you will caed nond lethal aid to ukraine. that includes promises to supply humvees both armoured and unarmoured. dronesment but they haven't yet agreed to supply lethal aid, weapons in particular anti-tank weapons that both people who are on the front linesing soldiers who are on the front lines as well as officials in kiev desperately want. >> srennivasan: so what's the reaction in moscow where are you? >> the reaction in moscow has been strong negative suggestions by president putin spokesmen that this could destabilize the situation in the country. we interpret that to mean new conflicts or new outbreak of violence in the southeastment although there have been a lot of terrorist acts in several cities in ukraine as well. but the kremlin has really

drawn a red line at supplying lethal aid. so i think that it's not absolutely certain that the arrival of these military trainers is going to change the situation in the southeast. what seems far more important to them is that countries like the united states and europe and even israel don't supply weapons to you current. that seems to be their real red line. >> all right andrew roth from "the new york times" joining us via skype from moscow. thanks so much. >> thanks. >> sreenivasan: in a decision with possible repercussions for the world economy, china's central bank announced new banking rules today. they're meant to help spur bank lending and to combat slower economic growth. even so, some analysts questioned whether the move would enable china to reach its 7% growth target for 2015, its lowest in nearly a quarter of a century. recent comments by f.b.i. director james comey have led to a diplomatic flap between the united states and poland. poland's foreign ministry

summoned america's ambassador in warsaw for a meeting today after comey said that nazi germany had been aided by accomplices in poland and other countries. the polish embassy in washington sent a letter to the fbi director saying he had, in their words, accused poles "of perpetrating crimes which not only did they not commit but which they themselves were victims of. >> sreenivasan: and now to south africa, this weekend the leader of that country, jacob zuma canceled an overseas trip. this following days of violence there against immigrants. for more, we are joined now via skype from johannesburg by david smith of the guardian newspaper. is is david, we should say you are on battery power. you are talking to us during a blackout. what has been happening there over the past few weeks,? what is the source of this violence? >> there has been an outbreak of xenophobic violence targeting many african foreign nationals living in south african and at least six deaths and the u.n. estimates more than 5,000 people displaced many to transit camps set up

around major cities. it's what many would say is due to underlying problems of unemployment and poverty. and has been condemned by the south african government an many civil society leaders. and really a flare-up and a trend that we have seen over at least ten years. >> srennivasan: the people that are being attacked where are they from? >> zimbabwe in many cases maliwe. mozambique many from nigerian. a few other african countries. sometimes they are fleeing conflicts and violence in their homeland. sometimes they are economic migrants. >> srennivasan: how about is the unemployment situation in south africa that is prompting some of this violence. >> the official unemployment rate is about one in four people. most experts would say that is actually an understation it is closer actually to one in threement and the worst affected of all are younger black people where some

estimate half. >> srennivasan: this has also prompted a reaction from south africa's neighbors. tell me a bit about that. >> yes, there has been demonstrations at several south african embassies around africa, there has been an incident where south african vehicles were pelted with stones in neighboring mozambique. there have been threats to close south african businesses. this sadly has really driven divisions between south africa and the rest of the continent. >> srennivasan: david smith joining us via skype from dark johannesburg tonight, thank you. >> thank you. >> sreenivasan: turning to news in this country: the chairman of the house committee on homeland security said today the recent arrest of an ohio man for allegedly plotting a terror attack illustrates the heightened threat now facing the united states. >> it's the first foreign fighter case we've seen of an american citizen travelling to syria, training with al qaeda,

al nusra, and then returning to the united states under instructions by al qaeda operatives to conduct a terrorist attack on american soil. that is what's hugely significant about this case. >> sreenivasan: it's been a violent few days in parts of chicago. authorities there say at least two people were killed and at least 18 wounded in a series of shootings since friday afternoon. the number of shootings were up 40% during the first three months of 2015 compared to last year. the number of murders is up 29%. authorities in neighboring indiana are having a difficult time controlling that h.i.v. outbreak from shared needle use. the state's department of public health says there are now 130 documented cases, with 24 new cases reported this past week. indiana has implemented a needle exchange program to try to curb the outbreak. that 61-year-old florida postal worker who violated national airspace by landing his gyrocopter onto the grounds of the capitol is now back in florida under house arrest. doug hughes's next schedule court appearance in washington is three weeks from now. the incident has prompted a full-scale security review since hughes was able to fly under the

radar near so many monuments through restricted airspace. the nation's second most populous state texas, is on the verge of passing legislation that would allow residents there with concealed handgun licenses to openly carry the guns in holsters. the bill cleared the texas house friday. the state senate had already passed a similar version of the bill. the governor has said he will sign any legislation that expands second amendment rights. and imagine traveling from chicago to new york by train in just more than two hours. that might be possible sometime in the future if a train now being tested in japan is put to use in this country. the magnetic levitation bullet train hit a record 366 miles an hour during a test in that country a few days ago. its manufacturer says it wants to export the technology to the united states. news from washington tonight

that for nearly two decades during the 1980s and 1990s, top fbi forensic investigators routinely gave flawed testimony overstating the evidence they had against criminal defendants. in more than a dozen cases, the defendants were later executed or died in prison. spencer hsu broke the story in today's washington post. he joins us now from washington. so i say this is a watershed moment in one of the country's largest forensic >> what has been found has been as you say that for more than two decades nearly every examiner and nearly every criminal trial in which fbi experts gave testimony against criminal defendants they overstated the strength the the significance of a match. >> srennivasan: so you say said that about a quarter of all the wrongful con vixes of people that have been exonerated later on the testimony of hair examiners or bite mark comparisons have actually helped sway juries and judges.

>> that's right. out of about 329 dna examinations more than a quarter involved invalid forensic science. one of the issues here is that unlike dna whiches with developed by scientists for scientists, a lot of the earlier pattern-based techniques comparing hair fiber bite marks even tracing bullets to being fired from specific weapons were developed in the lab by law enforcement. >> srennivasan: let's just say, for example if a defense attorney figures out that some of the evidence used in a trial for their client includes testimony from the nbi inspectors what does that mean for them. does that mean the judge automatically grant a new investigation or retrial? >> not necessarily. the fbu has offered to retest in cases where areas were made dna. if dna evidence is available. they have offered to drop procedural bars to post

conviction appeals as well. but for states most states make it difficult to challenge old convictions in the absence of dna. only california and texas have laws that permit it in cases when forensic evidence is recanted>xoju undermined by scientific advances. >> srennivasan: what is the fbi going to do to fix this? >> they have said that they will do a root cause analysis after all the reviews are completed am again they have offered to retest dna when dna evidence is available and to allow federal cases to be brought. they are agreeing to review scientific testimony and lab results standards to make clear what is erroneous and what is acceptable in 19 other techniques they say they did this for hair in 2012 when our reports surfaced. and they launched this review.

the ball now goes to state authorities as well as to the courts to determine if they will change these precedents more rigorously challenge the admissibility of scientific evidence. >> srennivasan: spencer hsu of "the washington post," thanks so much. >> thank you. >> sreenivasan: and now to our signature piece. you no doubt have heard about recent computer attacks against major corporations including target, sony, j.p. morgan chase, and anthem health. but criminals have also turned their attention to much smaller targets, even individual computer users. they're now using software to seize valuable personal data and hold it "hostage" until a ransom is paid. as the newshour's william brangham reports, tens of thousands of americans have fallen prey to these ransomware attacks. >> reporter: inna simone is retired a mother and grandmother from russia who now lives outside of boston.

last november, her home computer started acting strangely. >> my computer was working terribly. it was not working, i mean, it was so slow. >> reporter: a few days later while searching through her computer files, inna saw dozens of these messages, they were all the same. they read: "your files are encrypted. to get the key to decrypt them, you have to pay $500." her exact deadline - december her exact deadline - december 2 at 12:48 p.m., was just a few days away. all her files were locked, tax returns, financial papers, letters, even the precious photos of her granddaughter zoe. inna couldn't open any of them. >> it says, "if you won't pay within one week or whatever your fine will double. if you won't pay by then, all your files will be deleted and you will lose them forever and never will get back. >> reporter: inna simone, like hundreds of thousands of others had been victimized by what's known as a "ransomware" attack. hackers, who law enforcement

believe come mainly from eastern europe or russia, manage to put malicious software onto a victim's computer, often via an email attachment or a compromised website. that software then allows the hackers to lock up your files, or your entire computer, until you pay them a ransom to give it back. ransom demands have ranged from a few hundred dollars to several hundred thousand. justin cappos is a computer security expert at new york university. >> it will actually lock you out of the files, the data, on your computer. so you'd be able to use the computer but those files have been encrypted by the attacker with a key that only they possess. it's frustrating because you you know your photos and everything is there and could be accessible to you. but you have no way of being able to get at it because of this encryption that the attackers are using. >> reporter: inna was panicked. computer technicians were no help. she didn't want to call the police, her husband at first said don't pay the ransom, but

she wanted those files back. in their 'iransom note', the hackers wanted to be paid in bitcoin, the largely untraceable digital currency, and have it put into their anonymous account. inna had never heard of bitcoin but the hackers, in one of their many touches of what you might call "customer service," provided all sorts of helpful facts and links and how-to guides about bitcoin. >> if you see the ransom note you can see, "oh, they try to reassure you about bitcoin." we have got screen shots or here is a link to some kind of a guide that talks you through the whole process, and here's a list of providers with a little kind of yelp-like reviews next to each one that kind of explain their strength and weaknesses. it's incredibly sophisticated. >> reporter: after days of debate, inna decided to pay. she sent a money order to a bitcoin seller, but it was thanksgiving and a huge snowstorm hit boston which meant the check only arrived the afternoon before her deadline.

and, in that delay, bitcoin's exchange rate had changed, and now her check didn't cover the full $500 ransom, it was about $13 short. her last resort was this bitcoin atm machine in brooklyn, ny, conveniently not far from her daughter alina's apartment. >> it's very kind of spooky looking a.t.m. it has no buttons. it just had a slot that you feed your money into. >> reporter: tuesday afternoon, the full ransom was sent to the hackers account. but it was two hours late. inna added one short message with her payment. >> i wrote: "i wish you all will drop dead." >> reporter: the f.b.i. doesn't have complete data on how often these attacks occur. computer security researchers estimate close to a million users have been hit globally during the last year. one tech firm estimates that more than a quarter of victims pay the ransom, which cyber security experts discourage because they don't want to encourage more hacking. and it's not just individuals

who get hit: hackers have hit several local police stations. we heard of law firms being targeted. even the city of detroit had its data held for an $800,000 ransom by hackers. the city didn't pay. >> when you think of a technology hack, you think of data or files that are being destroyed, or taken, ransomware i learned, doesn't work the way. >> reporter: last month, terry van zoeren had to learn all about ransomware when his southern new jersey school district got hit. hackers compromised the entire district's computer system, causing problems with hard drives throughout the system: administrators, those in the classrooms, the computers that processed kids' lunch payments, even the standardized tests that were going on when the hack occurred. >> we had to shut down student testing for a number of days until we got control of the p.c.'s. and there were 100's of p.c.'s in the district. >> reporter: van zoeren said the

hackers demanded 500 bitcoin which at the time was about $128,000 in ransom. school officials didn't pay. there's obviously no guarantee paying up gets your data back. instead, they called the local police. school officials says no student or parent data was stolen, and after a costly, elaborate rebuilding of their network they were able to get back up and running. nyu computer scientist justin cappos says hackers go after such seemingly small targets because they're pretty easy: victims often inadvertently download the viruses themselves by clicking on those email attachments. besides, he says, the risks of getting caught are low, and if you cast a wide enough net, you'll get something. >> when you go fishing, you don't try to catch every fish in the ocean. you only wanna catch some. and if you catch enough of them, then it's been a profitable trip for you. >> reporter: when her mom got hacked, alina simone, who's a journalist by day, did some research into ransomware for a piece she wrote for the new york times. she says it's alarming how organized and easy it is to

carry out these kinds of attacks. >> there are people making viruses, selling viruses. there are distributors whose specialty is distributing viruses. these perpetrators, they don't have to know a line of code. they can just buy a virus and then hire a distributor and send it out. and it's kind of just an off the shelf, you know-- >> reporter: wow. plug and play corruption. >> right. and so that's sort of the scariest thing that, just one person can just unleash all of this chaos and malice on the world with very little effort. >> reporter: her mom's story, however, wasn't over. inna had paid the hackers $500, but rather than releasing her files as promised, they sent her this message. it said, "you did not pay in time for decryption." remember, she'd paid two hours late, now the hackers doubled the ransom to $1,000, gave her another deadline, and said if she missed this one, they'd delete everything. >> if you won't pay by then, all your files are gone forever.

>> reporter: using a message board the hackers provided another customer-friendly touch, inna pleaded with the people she'd previously told to 'idrop dead:' "we had a snowstorm," "it was a holiday" and lastly: "i am only two hours late!" >> so first i sent them about all these obstacles and the fact that i was only two hours late and this is really harsh. >> reporter: did this feel strange that you're trying to communicate to a group of criminals, who knows where they are in the world, saying "you don't understand, the post office, the snow, thanksgiving, the long weekend" i mean you must've felt- >> but what else? i mean, this is the only option. it's either this or nothing. >> reporter: you didn't think it would work. >> absolutely not. >> reporter: but later that day the hackers released her files in full. >> sreenivasan: what can you do to protect yourself from being

hacked? watch our video guide on facebook at facebook.com/newshour. >> sreenivasan: this past week was the 70th anniversary of the liberation of the bergen-belsen concentration camp in germany where an estimated 50,000 people died. among its victims: anne frank. to mark the anniversary i.t.v.'s neil connery caught up with one of her childhood friends, who was reunited with anne in the camp shortly before anne died. >> i was the last friend schoolmate of anne frack to see her. >> nanette konig will never forget the last time she saw anne frack amid the horror of the holocaust a bitter sweat reunion for two girls just 15. >> she was only a skeleton. there was nothing left of her nothing.

i even wonder sometimes how could two skeletons have recognized one another. because both of us were just you know we were both starved to death. >> nanette watched anne receive the diary at a birthday party. she recalls anne determination in the camp that its story detailing her life in hiding from the nazis would live on. >> she told me that she had continued to write the book and that she would like to publish the book after the war. >> 70 years ago british troops helped to liberate -- where more than 70,000 people died during the holocaust. >> aichbe frack lost her life shortly before the camp was liberated. >> i can't remember whether we cried or not. we just fell into one another's arms. we hugged one another. we were, you know it was

very difficult. we just sort of held on to one another i guess. >> srennivasan: for more news before we leave you tonight hundreds gathered today in oklahoma city to could them rate the 20th anniversary of the bombing of the alfred p murrow federal building there 168 people including 19 children were killed in what was the deadliest act of domestic terrorism in the nation's history. and oncologists say a new blood test has proven reliable diagnosing several types of cancer according to the "new york times". the test called a liquid biopsy alternative to a traditional by op is-- biopsy predicted occurrences 3 months before sntsable on a ct scan. that's it. join us tonight on-line and tomorrow. i'm hari sreenivasan. good night.

captioning sponsored by wnet captioned by media access group at wgbh access.wgbh.org >> pbs newshour weekend is made possible by: corporate funding is provided by mutual of america-- designing customized individual and group retirement products. that's why we are your retirement company. additional support is provided by: and by the corporation for public broadcasting and by contributions to your pbs station from viewers like you. thank you.

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