The FBI is allegedly examining the deaths of two men who worked for a former FTSE 100 mining company at the centre of a long-running probe into allegations of corruption.
James Bethel, 44, and Gerrit Strydom, 45, were found dead in their separate motel rooms while on holiday together in the US in May 2015.
Bethel had left a senior position working for ENRC in the Democratic Republic of Congo in September 2014, while Strydom remained a general manager for the group in the country.
Police in Springfield, Missouri, put the deaths down to malaria, but reportedly never formally closed the case.
The Financial Times yesterday cast doubt on that conclusion, and reported that FBI agents had already been looking into the case by May this year, and that they had taken away some of the men’s possessions.
The claims form part of a book due out on Thursday by Financial Times journalist Tom Burgis – Kleptopia: How Dirty Money is Conquering the World.
ENRC has been under investigation by the Serious Fraud Office in the UK since 2014 amid suspicions of corruption around the acquisition of mining rights in Africa.
The company, which quit the FTSE, always denied wrongdoing and is suing the SF0 for £70m, alleging wrongdoing in the way it has conducted its case.
In January, Anna Machkevitch, daughter of ENRC co-founder Alexander Machkevitch, was convicted of failing to supply documents requested by the Serious Fraud Office.
She is not a suspect in the SFO’s probe, but had been asked to hand over records including diaries held on behalf of her father.
According to the FT, the SFO had contacted Bethel by the time he and Strydom travelled from South Africa to the US, while investigators were also “interested” in Strydom.
The paper unearthed emails from analysts at the US's Centres for Disease Control and Prevention suggesting the pair might have caught malaria on a fishing trip in Zambia weeks before their death.
However, a malaria expert who reviewed documents obtained by the Financial Times strongly doubted that two people would develop the disease at the exact same time and die on the same night.
In a statement in June 2015 confirming the cause of death as malaria, Springfield police said: "Autopsies were completed by the Greene County Medical Examiner and preliminary results show no signs of foul play.
"The cause of their deaths continues to be investigated, requiring toxicology reports and additional medical exams."
The SFO declined to comment. Springfield police department referred queries to the FBI. The FBI did not respond to a request for comment.
A spokesperson for ENRC commented: “Mr Burgis’ attempts to draw a link between these deaths to ENRC are entirely without substance.
"It appears as though he has been used to advance an agenda by ENRC’s adversaries, and is using sensationalist headlines in order to generate negative publicity around the company”.