SIFMA is not a government organisation but stands for 'The Securities Industry and Financial Markets Association - SIFMA'. This organisation is based largely in the US with offices in London and Hong Kong. It would seem very unlikely that SIFMA know anything about this claim apparently made by 'Frank Benson'. Certainly the officers working on Operation Iceman know nothing of this Mr Benson and say SIFMA has no involvement in their investigation.
I would be interested to know if anyone else has been contacted by 'Frank Benson' or someone purporting to be working for SIFMA.