The Alex Salmond inquiry has concluded that Nicola Sturgeon misled Holyrood, the PA news agency understands.
MSPs on the Scottish Government Handling of Harassment Complaints Committee voted 5-4 that the First Minister gave an “inaccurate” account of a meeting with her predecessor during the live investigation, according to a source.
This would amount to misleading the Scottish Parliament.
The decision is likely to increase pressure on Ms Sturgeon to stand down before May’s election, although it is unclear whether the act was deemed a resignation-worthy offence.
A Scottish Parliament spokeswoman said the committee is still considering its report.
It is expected to be published on Tuesday.
The Committee on the Scottish Government Handling of Harassment Complaints was set up after a successful judicial review by Mr Salmond resulted in the Scottish Government’s investigation being ruled unlawful and “tainted by apparent bias”, with a £512,250 payout being awarded to him for legal fees in 2019.
This latest development comes after Conservative MP David Davis used parliamentary privilege in the House of Commons to read out messages that he suggested showed a “concerted effort by senior members of the SNP to encourage complaints” against the former first minister.
According to Mr Davis, the messages disclosed by a whistleblower “demands serious investigation”, with one alleging the investigating officer in the case complained of interference by Ms Sturgeon’s chief of staff.
The message is alleged to have been sent by Judith Mackinnon to the Government’s communications director on February 6 2018, almost two months before the First Minister claims to have first known about the investigation of her predecessor.
A spokesman for the First Minister said: “The First Minister told the truth to the committee in eight hours of evidence, and stands by that evidence.
“It is clear from past public statements that opposition members of this committee had prejudged the First Minister at the outset of the inquiry and before hearing a word of her evidence, so this partisan and selective briefing – before the committee has actually published its final report – is hardly surprising.
“The question of the First Minister’s adherence to the ministerial code is being considered independently by James Hamilton, and we expect to receive and publish his report soon.”
Scottish Labour leader Anas Sarwar said: “I am not going to prejudge the outcome of the committee report and we await its findings, but if it does conclude that the First Minister has misled Parliament and potentially breached the ministerial code then that is incredibly serious.”
Scottish Conservative leader Douglas Ross said: “The Committee will publish its findings in the coming days and we will wait for that report.
“But we have already detailed that Nicola Sturgeon lied to the Scottish Parliament and for that, she must resign. All we’re waiting for is confirmation.”