Sheffield United's bankers asked for an explanation, following reports that the club was linked to money from a Saudi businessman related to former al-Qaida leader Osama bin Laden, a High Court judge has heard.
Mr Justice Fancourt, who is overseeing a dispute between Sheffield United's co-owners, was told on Wednesday how Santander had contacted the club in the wake of media reports about a link to money from the bin Laden family.
A lawyer told him how Santander "wanted an explanation".
Co-owners Kevin McCabe and Prince Abdullah Bin Mosaad Bin Abdulaziz Al Saud, a member of the Saudi royal family, have fallen out after starting to work together six years ago.
Mr Justice Fancourt is analysing their fight for control of the newly-promoted Premier League club, whose nickname is The Blades, at a High Court trial in London.
Sheffield United Ltd, a company controlled by Mr McCabe and his family, has alleged "conspiracy" and "unfairly prejudicial conduct", and wants damages.
UTB LLC, a company controlled by Prince Abdullah, wants declarations in respect of its rights under an investment and shareholders' agreement.
Prince Abdullah says the person behind a £3 million loan was Saleh Mohammed bin Laden.
He says Mr McCabe and his associates knew that, and says the name was mentioned at a meeting in Dubai in 2017.
Mr McCabe disputes Prince Abdullah's claims.
He says the money was a "bribe" given to Prince Abdullah by a different businessman.
Detail of claims and counter claims about the bin Laden link emerged during the trial last week.