Officers from Her Majesty's Revenue and Customs (HMRC) have visited Chelsea as part of a wider investigation into fraud in English football.
Newcastle United and West Ham were the subject of raids from the authorities on Wednesday, with HMRC confirming "several" people were arrested and a number of premises searched during an operation involving 180 officers.
Investigators also visited Chelsea's Stamford Bridge offices, although Omnisport understands this was a formal process during business hours for the purpose of gathering information.
No arrests were made, no property was seized and there were no allegations of wrongdoing made against Chelsea or any of its employees.
A club spokesperson for Chelsea said: "In connection with its wider investigation HMRC has requested certain information which the club will provide."
West Ham confirmed they are co-operating with the HMRC after officers were deployed in the north east and south east of England, as well as unspecified parts of France.
Financial and business records were seized, along with some computers and mobile phones.
A statement from HMRC read: "HMRC has arrested several men working within the professional football industry for a suspected Income Tax and 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."
Later on Wednesday, Newcastle released their own brief statement.
"Newcastle United can confirm that a member of its staff has this morning been assisting HMRC with their inquiries," it read.