Deputy Mayor for Policing Stephen Greenhalgh, who is also being quizzed by the committee, said that they were "not complacent" about the Sapphire rape investigations unit and were "not saying everything has been learnt".
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The mayor claimed 'international despots and criminal rings' were using phoney companies to buy homes in the capital.
Their twisted romance revolved around fictional Facebook characters, and the 8-year-old girl was seen as a threat.
Passengers were forced to jump the ticket barriers to avoid being crushed by the crowd.