Why use polonium?
Investigators still don’t know. The poison might be intended to send out a powerful message: that Litvinenko’s assassins had access to quantities of some of the most dangerous material in the world, and weren’t to be trifled with. Ironically, polonium is still providing police with their best clues – contamination has been found in a range of places visited by Litvinenko and his associates, and several of the people they came into contact with. Contamination could have been spread by physical contact if traces of the original poisoning solution remained on their skin. And from the day he was poisoned, Litvinenko would have excreted Po-210 in his urine, sweat and tears.
