The correspondence from the prosecution service was part of an intervention labelled “highly irregular” by Mr Salmond and led to a fractious week in Holyrood, with the Lord Advocate forced to answer questions in front of MSPs about the move.
The intervention saw the former first minister’s submission to the Salmond inquiry on the alleged ministerial code breach by Nicola Sturgeon published before being removed, redacted and reuploaded.
It led to Mr Salmond pulling out of his initially agreed evidence session before a frantic reorganisation for his appearance later the same week.
It also led to questions about the separation of the powers between the government and the prosecution service, with the Scottish Conservatives arguing the intervention pointed to the “inherent conflict” of the Lord Advocate’s dual role as law officer and head of the Crown.
James Wolffe QC and the Scottish Government rejected claims they acted improperly.
In a response to a Freedom of Information request, Holyrood officials confirmed two external solicitors, both representing two different unknown third parties, had contacted the Scottish Parliament’s Corporate Body (SPCB) to express their views on the submission’s publication.
The identities of the two third parties will remain unknown, with Holyrood stating that court orders for one party and requirements to protect personal information for the other third party would mean they both must be kept anonymous and their correspondence secret.
This is alongside correspondence from the Crown Office and Rape Crisis Scotland, who also contacted the SPCB during the deliberations around the publication of the submission.
Holyrood officials also confirmed three emails from one SPCB member, and legal advice from internal and external solicitors alongside senior counsel would be kept secret as their release was considered “not in the public interest”.
All correspondence between the Crown and the SPCB will remain secret, officials said, due to concerns around breaching court orders and to protect personal information.
Correspondence from Rape Crisis Scotland will also remain secret.
Reacting, the Scottish Conservative spokesperson on the Salmond Inquiry, Murdo Fraser, said there was “clearly severe pressure” exerted on Holyrood by the Crown.
He said: “The public deserve to know the whole truth about this affair. There was clearly severe pressure put on Parliament officials by the Crown Office, which resulted in this evidence being hastily unpublished.
“At every turn during this inquiry, the work of the committee was thwarted, whether by the government or the Crown Office in order to try and protect the First Minister.
“Parliament’s reputation has been badly damaged as a result and refusing to release key correspondence will only heighten suspicions over why such decisions were taken.
“While there is a clear duty to protect the names of any complainants, there should not be a blanket refusal over releasing discussions that were made at such a critical point in the inquiry.”
A Scottish Parliament spokesperson said: “The cross-party SPCB said in a written parliamentary question it is unable to publish the correspondence as the Crown Office requested it be treated as confidential.
"The SPCB respects that request given the sensitivity of the contents and the terms of the court order.”