November 25, 2006 -- British police are studying security camera footage in their investigation of the death by poisoning of former Russian intelligence officer Aleksandr Litvinenko.

He died on November 23 after being poisoned by a major dose of rare, radioactive polonium-210. Traces of the isotope have been found in three places Litvinenko visited before going to the hospital.

Public-health officials are warning anyone who might have had contact with Litvinenko to undergo medical tests, though they say the small amount of polonium does not pose a threat to the general public.

From his death bed, Litvinenko -- a strong critic of Russian President Vladimir Putin -- blamed his fatal illness on the Kremlin. The Kremlin strongly denies any involvement.

(compiled from agency reports)