turned into a vocal critic of russia,. when he was poisoned in london, it made headlines around the world. >> a lethal toxin in a cup of tea. >> it was a tiny little dirty bomb. >> it's nuclear terrorism. >> why was he? kilter unravel the mystery, we follow the tale of a dark conspiracy. >> are you frightened for your life? >> will me and confront the pain prime suspect. >> did you put polonium in the tea? >> and now, is a danger coming closer? >> we're two men may think waiting in the bushes. one man said shooting. >> an attack on the expert helping us with this story. >> people say it's never going to happen here. i know that can happen here, because it happened to my husband. >>, "dateline". former russian agent, alexander litvinenko former russian agent jim alexander litvinenko was a four critic of the russian government. but in his world, existent formation could make you a very rich man or a dead one. his murder set off an international investigation to discover who wanted in silence. here's richard engel with "spy games". >> a former russian agent, poisoned. a multi millionaire found dead in his bathroom. an investigative reporter, executed in front of her home. their lives had been interconnected. but what about their deaths? random acts? or as some suspect, part of an international murder conspiracy. that stretches across two continents and several world capitals. we'll investigate who wanted them dead and why. the case will take us from moscow two rome, two london, into a world of spies and spy catchers. of corruption and those who dare to expose it. a world in which murder happens, often. was there a hit list in my? >> sure that there was. >> but our story begins closer to home. on a late, winter evening, paul joyal, an intelligence analysts, was driving to his house just outside washington d. c.. it was quiet and dark. >> i got out of my car. there were two men waiting in the bushes. they jumped me. one man i fought with. and we ended up on the ground in a tussle. and this one man said to someone outside i didn't see, shoot him. so, i covered my heart with my arms and i turn to the side. and i was shot went through me. >> one shot? >> one shot and then i heard the click -- >> another? click >> right, and nothing happened. >> so your shot once, rolling to protect yourself. >> i hear a chamber to clear it. the gun jumped. at that point in time, the lights went on in my house. joyal's wife elizabeth heard the commotion. >> all of a sudden i hear a shot and that just flipped me up. i knew it was a gunshot. i knew it was a gunshot and i knew it was close. >> she opened the door and saw her husband. >> he's wearing a raincoat, a suit, a hat. and he's doubled over and you can see that he is in pain. he looks at me and says, i've been shot. >> the assailants had four out fled. elizabeth got joyal inside and called 9-1-1. >> as soon as that 9-1-1 call was done, i asked my son to lift my legs up. because i wanted to make sure that the blood was stays in the body >> you don't lose consciousness. >> elizabeth is a registered nurse. her training kicked in. >> there was no signs of external bleeding at that point. ? so, that kind of freaked me out, to. as a nurse, i know if it's not bleeding on the outside it's bleeding on the inside. >> an ambulance arrived and rushed joyal to the hospital. the nine millimeter bullet had torn through his bladder and intestines. they had to place him in a drug induced coma to see if his life. he was unconscious for a month. local law enforcement initially assumed the shooting was a botched robbery. but elizabeth joyal believed otherwise. >> i didn't want to seem like this crazy conspiracy theory woman. but i knew that it was not a carjacking. there's just no way. that it was just some random guy. it had to have been a planned attack. >> because nothing was stolen. the assailants had clearly been lying in wait. which is why when joyal came stumbling into the house with a bullet wound, he told his wife to call his business partner. a former russian spy master. >> i warned him, i was shot. >> so, if you're warning your russian business partner that you've been shot. you clearly didn't think the this was a botched robbery or car jacking? you thought this was related to your work? related to your russian connections? >> i don't think there's any doubt. >> someone had tried to kill him, just like the other guy in london. >> the other guy? a former kgb agent and friend of joyal's killed three months earlier in london. assassinated with a weapon so frightening and exotic, investigators almost missed it. a weapon that raise the specter of state sponsored murder. >> coming up -- we trace the steps of a mysterious attack from bus to barr, to deathbed. >> he was going through unspeakable torment. >> when "dateline" continues. tinues once-daily pill for moderate-to-severe plaque psoriasis for the chance at clear or almost clear skin. it's like the feeling of finding your back... is back. or finding psoriasis can't deny the splendor of these thighs. once-daily sotyktu is proven to get more people clearer skin than the leading pill. don't take if you're allergic to sotyktu; serious reactions can occur. sotyktu can lower your ability to fight infections including tb. serious infections, cancers including lymphoma, muscle problems, and changes in certain labs have occurred. tell your doctor if you have an infection, liver or kidney problems, high triglycerides, or had a vaccine or plan to. sotyktu is a tyk2 inhibitor. tyk2 is part of the jak family. it's not known if sotyktu has the same risks as jak inhibitors. find what plaque psoriasis has been hiding. ask your dermatologist about sotyktu for clearer skin. so clearly you. sotyktu. after advil: let's dive in! but...what about your back? 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[sfx: video game] emergen-c crystals. pilot: in a few minutes, we will land at london heathrow airport. >> in a few minutes we'll land in london's heathrow airport. >> we don't know why and who was behind it. >> american intelligence expert paul joyal eventually recovered from his near fatal shooting. in january 2015, he traveled with us to london to tell us the story of what happened to an important contact of his just a few months before joyal was shot. he was >> he was a law enforcement officer. work for the equivalent of the fbi. >> in counter terrorism? >> anti-corruption was what he was most interested in. >> his name was alexander litvinenko. sasha, to his friends. but his interest in fighting corruption had made him a lot of enemies. including in his own agency, the kgb, which was renamed the fsb. litvinenko was forced to flee russia with his wife and son. and seek asylum in london, where he quickly caught the attention of agents of the british intelligence service mi6. trenear - harvey was a former mi6 mi6 analyst -- the british wanted to for a find out what he knew about his former colleagues in the russian secret service. was he credible? >> oh, yes he. was >> credible enough that mi6 eventually began paying him a monthly salary. trading information for money was one-way for a former russian agent to make a living and his new home in london. then suddenly, in 2006, litvinenko who had always been fit and healthy, got very sick. >> it was just incredibly strong and heavy sickness. just suddenly and not stopping. >> litvinenko wife marina marie watch him weak waste away in just a matter of days. >> oh, it was awful. his here started to -- >> to fall out? >> yes, and he started to look like cancer patient treated by chemotherapy. >> i knew he was going through unspeakable torment. >> finally, they found in his blood. he might have been poisoned. >> why isn't. doctor suspected maybe he had ingested thallium. commonly found in rat poison and treatable with and antidote. >> finally. finally, we know what happened to sasha. and now we are all under control and he will be safe. >> but it wasn't under control. the antidote didn't work. did litvinenko it get better. he got worse. before long, even close friends like andrei nekrasov could barely recognize him. >> at possum point i said to myself, why should this be happening to this young, healthy, and some, athletic man? what is going on? >> he's fighting for his life. >> a fight litvinenko would lose. >> we're sorry to announce that alexander litvinenko died at university college hospital at 9:21 on the 23rd of november, 2006. >> but in the days just before his death, litvinenko did something remarkable. he knew he was dying and decided to help scotland yard detective solve his murder. he gave them a series of deathbed interviews. the transcripts provide a remarkably detailed account of his movements on that day he was poisoned. litvinenko's i can't start at aa 10 am when he received a phone call from an italian contact, mario scaramella, who just arrived in london, and insisted he needed to meet litvinenko immediately. he said he had urgent news. they agreed to meet that afternoon. at 3:10 pm, litvinenko and scaramella, were spotted on a security camera walking west on the street. they came to this sushi restaurant, where litvinenko ate lunch. scaramella said he wasn't hungry. litvinenko and scaramella parted ways after lunch, and at 3:48 pm litvinenko is caught on another security camera talking on his cell phone. litvinenko then walked about a mile to the millennium hotel, which is literally right across the street from the u.s. embassy. it's that modern looking building over there. this is one of the most secure neighborhoods in all of london. one of the hotel security cameras recorded litvinenko arriving ithy at:59 pm. he was there to meet andrei lugovoi, another former fsb agent. seen here wearing a black, leather jacket. lugovoi had his own security consulting firm. he and litvinenko have been talking about doing some business together in london. the two had met several times over the past year. this time, lugovoi brought along a buddy. a man name dmitry kovtun. he's the one in the black turtleneck. it was a quick meeting. litvinenko drink just half a cup of tea then left. around 5 pm, he caught a ride home. that night, he fell ill. and three weeks later, he was said. so, who slipped litvinenko poison that day? putting his murder into motion. litvinenko told scotland yard detectives before he died, he didn't know when or who had poisoned him. but he had no doubt that one or more of the man he had met that day, the two russians or the italian, was his killer. naturally, we wanted to talk to all three. >> coming up -- we track down the first suspect litvinenko named. >> are you frightened for your life? >> when "dateline" continues. the power goes out and we still have wifi to do our homework. and that's a good thing? great in my book! who are you? no power? no problem. introducing storm-ready wifi. now you can stay reliably connected through power outages with unlimited cellular data and up to 4 hours of battery back-up to keep you online. only from xfinity. >> alexander litvinenko, the home of the xfinity 10g network. former russian agent, the man friends called sasha, died without knowing what killed him. the results from a battery of tests came into late. that they did come in. it turned out he was killed by something far more lethal than common rat poison. >> it's polonium. >> polonium 210, to be exact. a rare and deadly radioactive isotopes. the news shop the world even though most people were exactly sure what polonium was. but paul joyal knew what it was and what it could do. that his friend effectively burned to death from redo activity. >> it's a horrible death. it's a gruesome death. he lived longer than any man normally would under those circumstances. and he lived just long enough, within 12 hours long enough, for them to finally determine that it was polonium versus something else. >> why if he had died 12 hours earlier would it had made any difference? >> because they wouldn't have found out. they would've marked the death certificate, as death unknown. he would've been put in the ground. it would've been just a mystery. unknown assailants. turn a page. move on. >> it's a key of this murder. polonium 210 was discovered. and now we exactly know what sasha was killed by. >> it's an almost perfect murder weapon. polonium has no smell, little taste, and without specialized equipment, it's undetectable. the amount that killed litvinenko slipped into something he ate or drank, was no larger than a green assault. that still 1000 times the lethal dose. and that tiny bit of polonium would've been enormously expensive. >> eight to $12 million to be able to get the portion that went into him. >> the who could get hold of such an expensive and exotic weapon. and how did they deliver the fatal dose? when detectives went step-by-step with litvinenko through the day he was poisoned, he named three potential suspects. the two russians and the italian. the first one we found was the italian. in rome we're on our way to see mario scaramella who hopefully can shed some more light on who killed alexander litvinenko, and why. scaramella has been a hard man to pin doubt. first he wanted to meet us in naples, then new york, then london. he finally agreed on rome and will have to find out why he has been so skittish. >> [speaking italian] >> how to describe scaramella? he's a lawyer. an academic. a security analyst. and also someone litvinenko never completely trusted. scaramella, you'll remember, is the contact litvinenko met at the sushi bar on the way day he was poisoned. >> litvinenko thought you poisoned him. >> yes. >> you didn't poison him? >> absolutely not. >> from his perspective, it does make sense. >> no, sure. everything is very strange. >> had scaramella been working for the italian government and sometimes used litvinenko as a source for investigations into the russian mob and spy rings. he was giving you names of russian mafia members? >> yes. >> you are connected to the intelligence service? >> exactly. >> something that was short to upset both the mobsters and the fsb. scaramella told us that in october, 2006, the month before litvinenko was poisoned, he began receiving frightening emails. the final message arrived on the very day of his last meeting with litvinenko. and what did that message? >> look, there are people ready to kill you. >> the emails amounted to a hit list. the next name up -- >> alexander. >> as in, litvinenko. scaramella says that's why he met with litvinenko in london. to tell him about the hit list. to warn him. but he says litvinenko didn't buy it. >> he said, mario, don't care about that -- >> he says it's b. s.? >> i think it's just a provocation. but please check on. >> but after what happened to litvinenko, scaramella says he takes the hit list seriously. are you frightened for your life? >> well do you have another question? [laughs] >> scotland yard questioned scaramella and eventually cleared him. why? because if you're looking for it, polonium is traceable. using specialized equipment, investigators were able to track it in people and in places. >> once polonium 210 had been identified, then across europe, like the slim from a slug all the way across, polonium was popping up everywhere. >> but not in scaramella. no polonium in his body or anywhere he had been. so, scotland yard took a hard look at the two russians, lugovoi and kovtun. when detectives retrace their steps, they found polonium contamination everywhere. >> we see the same fingerprints of the polonium in multiple places where they were. >> business offices. hotels. a hookah bar, a strip club, a soccer stadium, and the millennium hotel's pine bar were they last met litvinenko. that's where investigators hit the jackpot. these 3d graphics put together by scotland yard show the entire pine bar was contaminated with polonium. with extreme hotspots on a table and cheer. and the levels found inside this teapot, off the charts. paul joyal wonders how many people were unwittingly expos. >> do we know ultimately what the final cost of this use of polonium is? someone who is washing dishes in the pine bar, or in a hotel cleaning crew? >> five months after's death, scotland yard issued an arrest warrant for lugovoi. kovtun would come later. the two responded with a press conference in moscow, stating their innocence. >> [speaking russian] >> russia refused to extradite them. so we travel to moscow to find the men who were wanted in connection with litvinenko's murder. >> coming up -- the stakes get even higher as we confront the top russian official. when "dateline" continues. 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(guitar music)ee at with other programs i've tried in the past they were unsustainable, just too restrictive. with golo i can enjoy my food and the fear and guilt of eating is gone. >> i'm richard louis with their hours top stories. paris police arrested a man expected of a deadly knife attack close to the eiffel tower. it attacked a german tours who died from his injuries. two others were reportedly injured as well. they said the attacker was motivated by the killing of muslims in the middle east. and in arizona, u.s. border officials are closing a remote crossing because of an overwhelming amount of migrant arrivals. custom and border protection say the closure of that crossing will begin monday. now back to dateline! >> in the dead of winter, 2015, we arrived in moscow, in an effort to find out, we arrived in moscow, in effort to find out not only who killed former russian agent alexander litvinenko, but why. this is home to andrei lugovoi and dmitry kovtun. hunted by both scotland yard and interpol, suspected of killing litvinenko. around the world, they were villains in a tale of international intrigue and murder. yet here in russia, we found plenty of people who thought if the two did kill litvinenko, he probably had it come in coming. >> thank you very much for talking to us. >> in