Solicitor Keith Cox has quit as managing director of Oxford United Football Club following allegations concerning a $100m (£61m) fraud investigation in the US.

Cox's resignation came a week after The Lawyer revealed he was being investigated by the Office for the Supervision of Solicitors (OSS) following a complaint to the Law Society.

In his resignation statement, Cox says the OSS found there was no case to answer. But The Lawyer understands the investigation is still continuing.

A warrant for Cox's arrest was issued in September 1991 in the US District Court for Northern Florida. He is wanted for questioning in connection with “mail fraud, wire fraud, bank fraud, interstate transportation of stolen property and money laundering”.

There have been convictions in the US in relation to this matter, but all have been overturned on appeal.

The US Attorney's office in Pensacola, Florida, has confirms Cox is still wanted for questioning in the state.

He says the land deal dates back to 1986, and that “since then a number of principals and others involved have died”.

He says the indictments also related to other people. “At all times I was acting for clients.”