Sylvain Marveaux: Former Newcastle winger arrested in tax fraud probe
Former Newcastle winger Sylvain Marveaux is one of four people arrested in a tax fraud investigation by Revenue & Customs (HMRC).
French authorities said secret payments made to players and agents during deals between French and Premier League clubs are the focus of the probe.
Newcastle and West Ham's grounds were raided on Wednesday, as HMRC deployed 180 officers across the UK and France.
Marveaux, 31, joined Newcastle from Rennes in 2011 and made 39 appearances.
He returned to France to join Lorient last year.
Newcastle's managing director Lee Charnley was also arrested. He was released without charge at about 17:00 BST on Wednesday.
The French Prosecutor's office says 10 searches were carried out in France and four people were placed in police custody.
"The British authorities suspect secret payments may have been made to benefit certain players, their agents or third parties, allowing them to avoid paying tax on the income, or making social security payments," said a statement from the French Prosecutor's office.
French officials were asked by HMRC to provide assistance to their investigation in July 2016.
It took a further nine months before officers launched their raids on both sides of the Channel.
HMRC said it searched premises in the north east and south east of England, and seized business records, financial records, computers and mobile phones.
West Ham's London Olympic Stadium and Newcastle's St James' Park were among the locations raided.
HMRC officers also visited offices belonging to Chelsea FC "in connection with its wider investigation", a club spokesman confirmed.
But it is understood the club's premises were not raided and no arrests were made.
'Investigation creates instability and uncertainty'
BBC Radio 5 live sports news correspondent Richard Conway
The wheels of tax investigations turn slowly - so any sporting implications resulting from these arrests and raids may not be known for some time.
It would appear, on face value, that Premier League points and status for both West Ham United and newly promoted Newcastle United are safe for now.
However this "on-going" investigation risks creating instability and uncertainty for both clubs at a time when they both, for different reasons, need it the most. HMRC investigations of this scale are costly and only undertaken in the most serious of circumstances. This isn't going away anytime soon.
Rafael Benitez, celebrating promotion on Monday, told reporters it was good to work at a club where there's no backroom politics, a not so subtle reference to his tumultuous time at Real Madrid.
With Newcastle having documents seized, and further questions looming for its senior officials, he may have spoken too soon.