Rangers have confirmed that commercial director Imran Ahmad has left the club.
Ahmad's departure follows accusations that he had posted critical messages about manager Ally McCoist and former boss Walter Smith on a fans' website.
Ahmad and former chief executive Charles Green have also been reported to the Serious Fraud Office over allegations about last year's takeover.
The pair were already the subject of a club probe about their consortium's links with former owner Craig Whyte.
That had led to Green, 59, resigning as chief executive and announcing that he would be selling his shares in Rangers to bus tycoon James Easdale, whose family could make moves as early as Monday to increase their stake in the club further.
However, the two Englishmen reject claims by Whyte, 41, that the Scottish businessman was involved in the purchase of the club he put into administration last year.
The fraud office investigation follows claims made by the Worthington Group plc, which recently purchased a share of a company owned by Whyte.
Ahmad had remained in post until messages posted under a pseudonym on a fans' website were alleged to have come from his official Rangers email account.
The online comments apparently accused McCoist and Smith, now a non-executive director, of "trying to take control of the club without putting any money in".
Rangers said they would investigate the matter, while McCoist said: "Normally I can't speak for somebody else, but I can speak for Walter and I will speak for Walter.
"The fans can be totally reassured by the fact that all myself and Walter have ever wanted is the best for the club and that will continue to be the case.
"In no way, shape or form were we trying to take over the club in the last few months. Not at all.
"All we have attempted to do is the right thing for the club and I can absolutely assure the supporters that will always be the case.
"I don't think it's a necessity having somebody like Walter on the board, but I think it's an absolute godsend for myself and the normal supporters because we are safe in the knowledge that anything that Walter will do will be for the benefit of the football club.
"I don't think Walter would claim to be Scottish businessman of the year, but he knows enough about business and he certainly knows more about the football club, and the running of the football club, than probably anybody else on the board."
Meanwhile, it is understood that Easdale, of McGill's Buses, is aiming at a 29% stake in the club with a view to taking overall control and that his family could walk away from the club should they fail in that bid.