friends called sasha , died without knowing what had killed him. the results from a battery of tests came in too late, but they did come in. it turned out he was killed by something far more lethal than common rat poison. it s polonium! reporter: polonium 210 to be exact. a rare and deadly radioactive isotope. the news shocked the world, even though most people weren t exactly sure what polonium was. but paul joyal knew what it was, and what it could do. that his friend essentially burned to death. it s a horrible death. it s a gruesome death. he lived longer than he than any man normally would under those circumstances. and he lived just long enough, within 12 hours, for them to finally determine that it was polonium versus something else.
certainly didn t shed any tears when that happened, but laughs off the notion that the russian state was connected in any way. for one simple reason he thinks russian agents would have done a better job. i m surprised that the uk special services and the uk court accuses russia and lugovoi that with a bag of polonium they came to london and were just throwing it around. reporter: it just doesn t make sense to a lot of people that russia didn t kill him. for 100 years the russian special services have been using the kind of substances for killing people that you never will be able to recognize. why do we have to go into some kind of a bar and put it in somebody s tea cup and everybody s laughing at it? i mean, the state cannot be involved in that. reporter: litvinenko s friend paul joyal, who believes he was the target of a botched assassination, agrees that, in some ways, litvinenko s killers were indeed clumsy and careless. but he says that s because they
a person s weakest spot is his family, and i m a rational man. even if i had taken part in an operation, even if i had known what was in the container, would i take my family along? i am a rational man. i couldn t do it. reporter: not only did he continue to maintain his innocence, he offered his own theory about who poisoned the tea. could someone have put something in there without you noticing? no, why don t you think that the polonium may have been put there into the cup after our meeting the next day or by a guy from mi6? he brings the polonium and pours it into the cup. that s agatha christie stuff. reporter: mi6 is british intelligence. lugovoi says perhaps the brits killed litvinenko to embarrass russia. retired mi6 analyst glenmore trenear-harvey says that s nonsense. if for no other reason because mi6 would never use such an expensive weapon to kill anyone.
to unravel the mystery, we follow the tale of a dark conspiracy that may not yet be over. are you frightened for your life? we ll meet and confront the prime suspect. did you put polonium in the tea? and now, is the danger coming closer? two men were hiding in the bushes. one of them said, shoot him. an attack on the expert helping us with this story. people say, oh, it s never going to happen here. but i know it can happen here. because it happened to my husband. dateline: the real blacklist. good evening, i m richard engel. the word kremlin literally means a fortress in the center of a city. and for hundreds of years this fortress has been a seat of power and a center of intrigue. tonight, we ll examine the case of a former russian agent, alexander litvinenko. exactly what happened to litvinenko, and why, have been mysteries for a very long time. now, there are new leads.
reporter: why if he had died 12 hours earlier, would it have made any difference? because they wouldn t have found out, they would have marked the death certificate as death unknown. he would have been put in the ground and it would have been just a mystery unknown unknown assailants. turn the page, move on. it s the key of this murder. polonium 210 was discovered and now we know exactly, sasha was killed by polonium 210. it s an almost perfect murder weapon. polonium has no smell, little taste, and without specialized equipment. it s undetectable. if you re not looking particularly for polonium, then you would not able to discover it. do you know? it will be everywhere, but you don t know this. reporter: the amount that killed litvinenko was slipped into something he ate or drank and was no larger than a grain of salt, but that s still a thousand times the lethal dose. and that tiny bit of polonium