The former SAS sniper, called Soldier N, who had previously claimed that Princess Diana was 'assassinated' by the elite regiment, could reportedly be involved in an illegal gun running business.
This news has raised serious questions over the key witness' credibility in the case, the Daily Star reported.
According to court documents, almost 20,000 pounds in US dollars and Iraqi dinars were paid into Soldier N's accounts after he came back from Iraq in 2004.
Other files claimed that Soldier N, who did not have a private firearms licence, was exchanging emails in 2009 with a UK gun dealer about a rifle, thought to be a CheyTac M200 "Intervention".
However, the dealer, who runs a licensed company, claimed that the messages were about test-firing the rifle and had been legitimately signed off by the SAS.
But the papers said that the weapons were unlikely to be used for Service weapons and the inference would be that they were for use on other firearms.