Rangers have appointed an independent law firm to look into connections between former owner Craig Whyte and Charles Green and his associates.
Pinsent Masons will work in conjunction with financial experts from Deloitte as the club look to get to the bottom of the issue.
Green stepped down as chief executive last week following a number of claims surrounding his dealings with Whyte before his consortium took control of the club last year.
Green has previously refuted claims that he was working with Whyte, saying: "These are distorted and malicious allegations coming from a man who is completely discredited and now under police investigation."
There has been no announcement form Ibrox over the appointment of an interim replacement for Green, who stepped down with immediate effect on Friday.