Letters 'revealed secret Russian hit squad'

Detectives are investigating letters smuggled out of Russia purporting to show the existence of a secret squad set up to target poisoned spy Alexander Litvinenko and others.

Scotland Yard has been passed copies of two letters apparently penned in jail by former Russian intelligence officer Mikhail Trepashkin, in one of which Mr Litvinenko is warned that both he and his family are at risk.

Mr Litvinenko's London friend Alex Goldfarb said scans of the letters came into his possession on Thursday

and he passed them to Scotland Yard.

Mr Trepashkin, who worked for the KGB's successor the FSB until 1997, was