The KGB used polonium to assassinate former spy Litvinenko, although thallium was initially considered, which was instead used by the KGB to poison another Russian dissident, Nikolai Khokhlov, in 1957.
The KGB used polonium to assassinate former spy Litvinenko, although thallium was initially considered, which was instead used by the KGB to poison another Russian dissident, Nikolai Khokhlov, in 1957.