Newcastle United and West Ham have been raided by Her Majesty's Revenue and Customs due to an investigation into their transfer dealings.
Newcastle's managing director Lee Charnley has been arrested, and London Stadium and St. James Park were the subject of warrants this morning.
According to the Independent, Charnley has been largely responsible for the clubs' recruitment over the years. He spoke recently about Newcastle's transfer strategy post-relegation, saying:
"Our approach, following relegation, was to make further sizeable investment in our playing squad in preparation for the EFL Championship season ahead and our annual wage bill is, we believe, still above and beyond many current Premier League teams.
"Whilst not without financial risks, this strategy was adopted in order to maximise our chances of promotion at the first time of asking."
The news comes only two days after Newcastle secured promotion from the Championship with a 4-1 win over Preston.
HMRC say they have arrested "several men working within professional football industry for suspected income tax & national insurance fraud."
"180 HMRC officers have been deployed across the UK and France today. Investigators have searched a number of premises in the North East and South East of England and arrested the men and also seized business records, financial records, computers and mobile phones.
"The French authorities are assisting the UK investigation, have made arrests and several locations have been searched in France.
"This criminal investigation sends a clear message that, whoever you are, if you commit tax fraud you can expect to face the consequences. As this is an ongoing investigation HMRC is unable to provide any further detail at this time."