Evidence that individuals acted against the interest of creditors could lead to them being banned from being directors for up to 15 years.
The apparent lack of progress being made by the DTI had led some to assume the inquiry was dormant, but the YEP has learned that interviews were recently held with a number of the United board members who were left in charge after Mr Ridsdale quit in 2003.
They are understood to include one-time chief executive Trevor Birch and Prof John McKenzie, who spent eight months as chairman.
Ex-finance director Neil Robson is also thought to have been among those spoken to by the DTI's disqualification unit in Manchester.
They are said to have been asked for their opinions as to the degree of recklessness surrounding United's financial dealings.
There is no suggestion of any wrongdoing on the part of Mr Birch, Prof McKenzie or Mr Robson.
Deborah Wilson, head of the disqualification unit refused to comment on the investigation when contacted by the YEP.