Smoking Gun

Note to self: when attempting to poison international spies, do not use a substance that will leave a radioactive trail everywhere you go before and after the dirty deed. From this article:

Investigators believe the poison cocktail was likely to have been manufactured in a guest room at the hotel, a short walk away from the US Embassy. Significant traces of polonium-210 were found in a fourth-floor room, which was occupied by a visiting Russian.

One of the Russian guys here at work says he doesn't believe KGB is responsible because "they're not that stupid."