assassination, agrees that in some ways litvinenko's killers were indeed clumsy and careless. but he says that's because they were probably just pawns in a much bigger game. >> do you think that any of them knew what that substance was? do you think that they knew they were handling polonium? >> reporter: why wouldn't they have known what they were handling? >> because you don't want them to know. >> reporter: but they could have done a better job not spreading it all over the place if they knew. >> they also might say no, there's no way i'm going to do that. >> reporter: i don't want to handle that radioactive material? >> i am not going to kill myself in the process. ing to kill mysef in the process my digestive system used to make me feel sluggish but now, i take metamucil every day.