A property entrepreneur has been bailed after he was arrested in connection with an investigation into alleged fraud and money-laundering.
Leeds-based Simon Morris was questioned by officers on Wednesday last week about a land deal involving a business contact in the city.
His father, Bryan Morris, was also arrested, along with seven others. All nine were later released on bail.
Bryan Morris told a local newspaper: "Me and Simon were locked up for 12 hours in separate cells.
"We are completely innocent, this was just an amount of money given to us as a reservation fee for a piece of land that Simon owned."
Earlier this month more than 30 companies owned by Simon Morris, a Jewish former director of Leeds United Football Club, went into administration with debts in the region of £50 million.
The allegations are not linked to the collapse of the businesses, which he has blamed on the economic climate.
Det Ch Insp Paul Langan confirmed that West Yorkshire Police's economic-crime unit was carrying out enquiries into "a business transaction".
In a statement, Mr Morris's solicitor, Stephen Hipps, said: "He has not been charged with any criminal wrongdoing or even unsavoury business activity.
"He has fully co-operated with the police as much as he could in this enquiry, which in fact directly involves others and not directly our client.
"We wish to stress further on his behalf that our client's current trading problems are in no way connected with this enquiry."
The 31-year-old was the youngest person to be included in the Estates Gazette property-industry rich list last year and was believed to have a personal fortune of around £70m.