The treatment of whistleblowers by the UK's financial watchdog must be investigated following the death of a British trader who exposed evidence of links between US commerce secretary Howard Lutnick and Jeffrey Epstein, MPs have said. Simon Andriesz, a former senior employee of BGC Partners - the international firm of financial brokers founded and run by Lutnick before his appointment by US President Donald Trump - died last month in Thailand. Earlier this year, Andriesz raised concerns with the Financial Conduct Authority (FCA), the FBI and other watchdogs about evidence he had uncovered of business links between Epstein and Lutnick. It cast doubt on Lutnick's public statements about his associations with the late sex offender. A group of UK MPs have now said his death raises "deeply troubling questions" about the way whistleblowers can be treated when they approach the FCA - the financial regulator - with concerns about wrongdoing and subsequent retaliation. Andriesz uncovered evidence that Lutnick had sought, in Andriesz's words, to "buy a prince", offering to go into business with Andrew Mountbatten-Windsor in 2013 and utilise the former prince's contacts to attract investments, in exchange for a loan of £1m. BGC told the BBC the proposed joint venture did not go ahead. Andriesz also submitted evidence to the FCA to support his allegations of misconduct at Lutnick's former firm, including an allegation that cash from the pool of commission money set aside to pay brokers' bonuses was "embezzled" for improper purposes – an allegation the firm has denied. Weeks before his death, Andriesz told a public event led by MPs, whistleblowers and campaigners calling for fairer regulation that he felt "thoroughly let down" and had been put through "absolute hell" by the FCA, to whom he had sent evidence of what he regarded as whistleblower retaliation b