A British agent has told The Times he has been contacted by Britain's tax authority, HM Revenue and Customs (HMRC), in the wake of its investigation into suspected tax evasion.
"They asked if I was available to talk at some time," agent Barry Silkman said. "I said I was and they said, 'You may hear from us again, you may not.'"
Silkman confirmed he helped to broker Demba Ba's move to West Ham United from Hoffenheimin January 2011 and he received fees from Ba's agent for his future transfers to Newcastle United and then Chelsea.
He said everything was "completely above board," adding: "I did the introduction at West Ham and his agent said I would also get paid if he moved again in England and he was as good as his word."
On Wednesday, British tax authorities arrested "several men working within professional football" after co-ordinated raids of premises in the north east and south east of England.
Nearly 200 officers from HMRC took part in the raids, seizing computers, mobile phones and paperwork, with the French authorities making similar raids and arrests at locations in France.
Press Association Sport reported that one of the raids was on Newcastle's St James' Park ground and the club's managing director Lee Charnley was among those arrested.
It has also been reported that the London Stadium was raided and a West Ham spokesperson said: "The club is cooperating fully with HMRC to assist their enquiries. No further comment will be made at this time."
On Thursday, Lorient midfielder Sylvain Marveaux was among four people briefly detained in France as part of the investigation.