The London-based hedge fund, Moore Capital, was one of the firms raided by the City watchdog the FSA, the BBC has learned. One person at Moore Capital and five other City workers are being held. Those arrested are suspected of taking part in a long-running insider-dealing scheme. The arrests came after 16 addresses were searched in a joint probe by the Financial Services Authority (FSA) and Serious Organised Crime Agency (Soca). Documents and computers were seized from premises in London, the South East and Oxfordshire. It is the FSA’s biggest operation against insider dealing.