SNP MSPs on the Salmond inquiry have accused opposition members of “the politics of desperation” after conclusions reached in by the committee were leaked.

The committee, set up to investigate the botched handling of harassment complaints against Alex Salmond, voted 5-4 on Thursday to conclude Nicola Sturgeon had misled them in her written evidence over a meeting with her predecessor.

According to Sky News, the Holyrood committee also finds it “hard to believe” Ms Sturgeon’s testimony of when she first heard about concerns relating to the former first minister’s alleged behaviour.

Ms Sturgeon has claimed she first became aware of any potential inappropriate conduct by her predecessor after a media inquiry in November 2017 about an alleged incident involving female Edinburgh Airport staff back in 2013.

MSPs on the committee reportedly believe Ms Sturgeon did have knowledge of concerns about Mr Salmond’s conduct before the time period she claimed – and therefore should have acted upon that information.

Further leaks suggest a passage has been included in the committee’s report explaining how a majority of members are “concerned” at how it took Ms Sturgeon two months to tell the head of Scotland’s civil service, Permanent Secretary Leslie Evans, that she knew about the investigation.

In an unexpected step, three of the four SNP members on the committee, Stuart McMillan, Alasdair Allan and Maureen Watt, released a statement on Friday attacking their fellow committee members.

The SNP members accused the opposition members of using their majority on the committee to “insert 11th-hour predetermined political assertions that have no basis in fact”.

“This committee was meant to carry out a dispassionate search for the truth,” it said.

“But, at the very last minute, without full consideration of the evidence, the opposition railroaded through their prejudged assertions based purely on political considerations.

“On the question of the First Minister offering to intervene, there are two sides of the story and we have evidence from both sides, but opposition MSPs chose not to reflect that by selectively referencing only the evidence which supported their preconceived narrative.

“We have also heard clear, consistent evidence that the First Minister had no knowledge of concerns of inappropriate sexual behaviour by Alex Salmond before November 2017.”

The statement added: “Yet, without a shred of evidence to the contrary, the opposition simply used their majority on the committee to insert 11th-hour predetermined political assertions that have no basis in fact. That is simply disgraceful and wrong.

“For the opposition, this was never about the truth. It was never about the evidence and, shamefully, it was never even about the women. All of these are being sacrificed in pursuit of political ends.

“This is the politics of desperation by the opposition members.”

Committee convener, Linda Fabiani, also an SNP MSP, did not put her name to the statement, but said earlier in her capacity as convener she was “dismayed by the damage this may do to the value of the committee’s work which I have long hoped would improve the treatment of the complainers of sexual harassment”.

The First Minister, who is now facing a vote of no confidence from the Conservatives on Wednesday if she refuses to stand down, accused members of the committee of a “partisan leak”, and a spokesman for Ms Sturgeon said she “stands by every word of evidence”.