MSPs say an inquiry into the Scottish government’s handling of complaints against Alex Salmond cannot currently proceed because of “obstruction”.
A committee was set up to look into the botched investigation, which the government admitted had been unlawful.
But convener Linda Fabiani said it had been “completely frustrated” by the lack of evidence being handed over.
She said the committee was still awaiting responses from the government, Mr Salmond and SNP chief Peter Murrell.
This has meant the committee has been unable to hold further evidence sessions, with Ms Fabiani saying the inquiry “simply cannot proceed at this stage”.
Another member of the committee, Labour MSP Jackie Baillie, claimed that it was being treated as a “laughing stock” by the Scottish government and “many others involved in this affair”.
And Murdo Fraser of the Scottish Conservatives, who is also on the committee, said the inquiry was becoming a “whitewash”.
The Scottish government insisted that it was cooperating fully with the inquiry and “strongly rejects any suggestion of obstruction”.
It also said it intends to initiate legal proceedings aimed at allowing the release of further documents to the committee.
The committee was established in the wake of a judicial review court case where the Scottish government admitted its internal investigation of two harassment complaints against Mr Salmond had been unlawful.
The government had to pay out more than £500,000 in legal expenses to the former first minister, who was later acquitted of 13 charges of sexual assault in a separate criminal trial.
A number of witnesses – including Permanent Secretary Leslie Evans and Lord Advocate James Wolffe – have given evidence to the committee so far.
However sessions with other witnesses – including Mr Salmond, his successor Nicola Sturgeon and her husband, Mr Murrell – have had to be put on hold while MSPs on the committee attempt to have various documents handed over.
The committee has been locked in a dispute with the government about the release of documents relating to the judicial review, while Mr Salmond’s lawyers said they had been warned it would be against the law for him to release some other documents.
Ms Fabiani, who is an SNP MSP and one of Holyrood’s deputy presiding officers, urged everyone involved to “engage productively” with the cross-party group “so it can get on with the task in hand”.
She said: “The committee continues to be completely frustrated with the lack of evidence and, quite frankly, obstruction it is experiencing.
“We had hoped to be in a position to hear further oral evidence, but with responses still outstanding from the Scottish government, the chief executive of the SNP and the former first minister, all of this means that we simply cannot proceed at this stage.”
Ms Baillie went further, saying that “the government and others are treating this committee as a laughing stock”.
She added: “The Scottish government and indeed many others involved in this affair have demonstrated contempt for this committee and its aims.”
And Mr Fraser said “it now appears that this inquiry will be a whitewash”, saying Ms Sturgeon had “undoubtedly broken her promise to release all materials that the inquiry requested”.
The first minister had said in January 2019 that “the inquiries will be able to request whatever material they want, and I undertake today that we will provide whatever material they request”.
Mr Fraser said that if the government did not release the documents members had asked for, it meant Ms Sturgeon “has misled parliament”.
A spokesman for the Scottish government said it had already provided the committee with more than 1,000 pages of relevant material, with government witnesses also providing “many hours of oral evidence” so far.
He added: “Where further information or clarification has been required by the committee, we have followed up quickly in writing, including to correct inaccurate assertions that documents had not been provided when they had in fact already been submitted.
“As the committee has recognised, the inquiry involves sensitive information. We are providing the relevant information requested so far as is possible given the confidentiality, data protection and legal restrictions that apply and will continue to do so.”
Leslie Evans, the Scottish government’s top civil servant, has previously earlier assured members of the government’s “commitment to cooperating fully with this committee”, saying “multiple dossiers of information” had been handed over.
She also said the government “acted in good faith” when investigating the complaints against Mr Salmond, saying it had “already learned early lessons” from the defeat in the judicial review.
Mr Salmond’s lawyers have written to MSPs saying the former first minister was “very keen to provide as much information to the committee as he is permitted by law”, but said there were some “legal restrictions” to this.
They said “pertinent material” had been handed over by the government during Mr Salmond’s trial, but said they had been told “it would constitute a criminal offence” for them to release it.
They added: “Our client cannot realistically provide a statement or documents which are partial and piecemeal. Any meaningful statement necessarily will involve reference to a large amount of the material which he is not permitted to release – and in some cases, even access or refer to.”
Mr Murrell, the SNP’s chief executive, sent a two-page written submission to the committee in August, saying he had only learned of the complaints against Mr Salmond when they became public in 2018.
He said “had the sense that something serious” was being discussed between Mr Salmond and his wife, Ms Sturgeon, during a meeting at their home in Glasgow earlier that year, but said that “Nicola told me she couldn’t discuss the details”.
Ms Fabiani subsequently wrote back to him to ask him to “revisit certain questions asked by the committee to assess whether there is further evidence you could usefully provide”.
She asked specifically for “relevant emails, minutes, notes, texts, papers and WhatsApp messages from all levels of the SNP”.
An SNP spokesman said: “Mr Murrell provided written evidence by the original 4 August deadline.
“The committee’s additional requests of 9 September set no deadline for a response – however, we are in active dialogue with the clerks about the further information sought.”
One SNP MP – former Holyrood Justice Secretary Kenny MacAskill – has called for action to be taken against Mr Murrell over WhatsApp messages he is alleged to have sent concerning the case.
Mr MacAskill said he had been sent an anonymous letter “that purported to be messages from the SNP chief executive to another senior staffer” which “suggested pressure be brought to bear on police investigating Alex Salmond”.
In the committee’s last public meeting, it heard claims from Mr Salmond’s top civil servant that he “could display bullying and intimidatory behaviour” – although he said there were “no suggestions of sexual misconduct”, and that issues were generally dealt with “informally”.
Members have also heard claims from unions that dozens of civil servants had raised concerns about the behaviour of “multiple ministers in multiple administrations”.