The Scottish Police Authority is under pressure to explain why it approved the return to work of Chief Constable Phil Gormley without consulting investigators looking into allegations of bullying.
Mr Gormley, who has been on leave since September, had been told he could resume his duties in November before an alleged “intervention” by Justice Secretary Michael Matheson.
It has emerged the SPA failed to speak to the Police Investigations and Review Commissioner (Pirc) – who is carrying out a number of investigations into the chief constable – before making the decision.
There are now calls for Mr Matheson to make a statement to the Scottish Parliament on the issue and for the SPA to explain why it acted without consulting the Pirc.
Mr Matheson is also expected to be called to give evidence by Holyrood’s audit committee alongside the SPA’s former chairman, Andrew Flanagan, and former chief executive, John Foley.
Mr Gormley, who denies the allegations against him, continues to collect his £214,000-a-year salary despite not being at work for the past four months.
According to a letter sent from the chief constable’s lawyer to Holyrood’s audit committee on 22 December, the SPA board had given its unanimous backing for Scotland’s most senior police officer to return to work before an “apparent intervention” by Mr Matheson.
In her own letter to the committee, the Pirc, Kate Frame, said she had advised the SPA on 11 December that there would be “no prejudice” to her investigations if the chief constable returned to work.
However, she said there had been “no consultation” from the SPA in advance of it announcing the chief constable’s period of leave, nor when Mr Flanagan told Mr Gormley he could resume his duties.
The first contact from the SPA regarding the issue was on 4 December from its new chief officer, Kenneth Hogg.
Lib Dem justice spokesman Liam McArthur said: “This reinforces what was evident during the course of last year, that the SPA had become dysfunctional under Andrew Flanagan’s leadership. Only he can answer the question why he did not feel consultation with the Pirc was necessary.
“It raises further questions about what the SPA was doing under his stewardship.
“There are serious questions to be answered around this whole process, including some for Michael Matheson.”
Scottish Labour’s justice spokesman, Daniel Johnson, said: “For months, the Scottish Government has separated itself from the crisis at Police Scotland and the SPA by claiming they are operationally independent.
“Now we have learned that the Cabinet Secretary may have directly intervened, by overturning a unanimous operational decision of the SPA.”
The Scottish Government said: “As was made clear at last month’s audit committee, the Scottish Government sought assurances that decisions by the SPA were being made on a fully-informed basis, including seeking the views of key individuals and organisations, including the Pirc.
“The Cabinet Secretary for Justice took the lead role in engagement with the SPA as this issue falls within his portfolio responsibilities.
“Any request for a parliamentary statement will be given due consideration.”
The SPA declined to comment.