well do you have another question? reporter: 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 slime from a slug all the way across, polonium was popping up everywhere. reporter: but not in scaramella. no polonium in his body or anywhere he d been. so scotland yard took a hard look at the two russians, lugovoi and kovtun. when detectives retraced their steps, they found polonium contamination everywhere. we see the same fingerprints of the polonium in multiple places where they were. reporter: business offices, hotels, a hookah bar, a strip club, a soccer stadium. and the millennium hotel s pine bar where they last met litvinenko? that s were investigators hit the jackpot. these 3-d graphics put together by scotland yard, show the entire pine
disturbing conclusion, which litvinenko himself reached before he died. mr. litvinenko came to the awful realization that he had been the victim of a political assassination by agents of the russian state. reporter: and in march 2015, an expert witness testified the polonium that killed litvinenko could have only come from russia. the kremlin ignored the inquiry. president putin s spokesman declined our request for an interview. and in 2015 putin gave lugovoi a medal, the order of merit to the fatherland, second class, for his work in the duma. you think russia will ever come clean and this will be known? i believe one day we will know this. it will be very obvious for people to decide. reporter: in the years she s been looking for answers, other questions have multiplied, other deaths have been recorded. there was boris berezovsky the russian oligarch litvinenko said
did you put polonium in the tea? and now is the danger coming pu closer? with two men waiting in the bushes, one man said shoot him.a an attack on the expert helping us about this story. people say, oh, it s never going to happen here. i know it can happen here because it happened to my husband. dateline: the real blacklist.
winning author and expert on russia i think anything that litvinenko was doing that came close to the source of putin s personal wealth would have been by far the most dangerous things that he could do. reporter: in addition to a possible motive there was also the means. paul joyal says the fact that polonium was used to kill litvinenko leaves little doubt as to who authorized the murder. so does that mean it had to be putin? it could have been someone else with access to come on, come on, you re not going to engage in an act of nuclear terrorism in downtown london without the knowledge of the office of the president. today we begin the open hearings in the inquiry into the death of alexander litvinenko. reporter: in january 2015, a public inquiry opened in london. it s a victory for marina, who, along with her attorneys, fought not eight-year legal battle to make it happen. on the opening day, her attorney argued the evidence leads to one
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 had put something in there without you noticing? translator: no. why don t you think the polonium may have been put there into the cup after our meeting the next day or by a guy from mi-6? he brings the polonium and pours it into the cup. that s agatha christie stuff. reporter: mi-6 is british intelligence. lugovoi says perhaps the brits killed litvinenko to embarrass russia. retired mi-6 analyst glenmore trenear-harvey says that s nonsense if for no other reason because mi-6 would never use such an expensive weapon to kill anyone. if the british wanted to kill him, then he would have fallen out of a hotel window. he would have been placed in front of a car. we d have spent $12 million in a slightly more cost-effective fashion. reporter: you would have made it look like an accident? indeed. things are done less