The Scottish Premier League have offered assurances that their investigation into alleged undisclosed payments by Rangers is progressing.
The SPL released a statement hours before a BBC1 Scotland documentary on the finances of Rangers, which includes examination of the Employee Benefit Trusts the club used in an attempt to reduce their tax bill.
An SPL spokesperson said: "The investigation into the EBT payments made by Rangers FC is being actively pursued on behalf of the SPL."
They continued: "All relevant documents, materials and information have been sought from Rangers FC and we look forward to receiving full co-operation from the club and its administrators in providing everything that it and they have access to and which is required for the investigation to be completed."
The SPL launched their investigation into the matter on March 5, with the probe covering the period stretching back to the competition's inception in 1998.
SPL rules prohibit payments to players that are not made "in accordance with a form of contract approved by the SPL".
The league instructed their lawyers, Glasgow firm Harper Macleod, to investigate the matter.
The BBC publicity around the programme, Rangers - The Men Who Sold the Jerseys, says it is based on "dozens of secret emails, letters and documents which uncover the truth behind the tax scheme which threatens the club's very existence, and reveals what went on behind the scenes in the run-up to Craig Whyte's infamous takeover".
Investigative reporter Mark Daly, who uncovered Whyte's disqualification as a director in a programme aired in October, revealed more details of his programme on Twitter.
He said: "Biggest EBT beneficiaries named, did Whyte really "dupe" Sir David (Murray) and questions over the administrators."