The continuing police investigation surrounding Birmingham City managing director Karren Brady is "contrary to natural justice", the club's chairman has said.
David Gold spoke out after 39-year-old Brady was re-arrested on Tuesday by officers investigating alleged corruption in English football.
Ms Brady was questioned by City of London Police and released on bail as part of an investigation into conspiracy to defraud and false accounting. She was first arrested last April, along with the club's co-owner David Sullivan.
In a statement released this morning, Mr Gold said the investigation had put the pair, who deny any wrongdoing, under "prolonged pressure".
He said: "Both David Sullivan and Karren Brady were originally interviewed in August 2007, re-interviewed in April 2008 and are now bailed until June 2009. They have had these matters hanging over them for 22 months.
"This seems contrary to natural justice and puts two people with life-threatening medical conditions under prolonged pressure. They have answered every question put to them and both vehemently deny any wrongdoing."
Mr Gold said the investigation centred on tax and national insurance payments, adding: "It is completely wrong that our managing director has been picked on and singled out. For the complete avoidance of doubt, I want to make this 100% clear that, as we stated before, this matter is all about PAYE and NIC on two players from 2002 and 2003, and absolutely nothing has changed.
"The figures alleged to be involved are not substantial and not material to the company. The club employs highly-respected accountants and auditors and has always provided them with complete access to their accounts and other financial information.
"The club believe that it would be more appropriate that questions about financial matters be directed to them."
Mr Gold stressed that the club "takes its financial responsibilities seriously".
A City of London Police spokeswoman confirmed that a 39-year-old woman was arrested as part of the continuing football investigation, but said it was not possible to provide details of the alleged offence, adding: "We have been working with HM Revenue and Customs (HMRC) from the outset of the investigation.
"The investigation has always focused on money laundering. The Fraud Prosecution Service has identified that tax offences may be involved."
Birmingham City released a statement stressing that Ms Brady had not been charged by police and "vehemently" denied any wrongdoing.
The statement said: "In the fullness of time, we believe the public will see that no offence has been committed by anyone at BCFC.
"The club continues to assist the police with their inquiries and have answered every question put to them."
In November 2007, officers arrested a series of high-profile figures in the national game in a controversial series of raids.
Other figures who remain on bail are believed to include former Portsmouth boss Harry Redknapp, the club's chief executive Peter Storrie, former chairman Milan Mandaric, former player Amdy Faye and agent Willie McKay.
Ms Brady became the UK's youngest football managing director when Birmingham City floated on the stock market in 1997.
She is also chairman of Kerrang! magazine and non-executive director of Channel 4, Mothercare and Sport England.
The HMRC said it was not making any comment.