but paul joyal knew what it was and what it could do.t 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