Alex Salmond has said he has “no doubt” that Nicola Sturgeon has breached the ministerial code.
The former first minister was speaking as he made his long-awaited appearance at a Scottish Parliament inquiry.
Mr Salmond gave an account to the committee of meetings he had with Ms Sturgeon that appeared to contradict her version of events.
But he said it was not for him to say whether Ms Sturgeon should resign if she was found to have broken the code.
Ms Sturgeon denies breaching the code, and has accused Mr Salmond of creating “wild” conspiracy theories that are untrue.
Her spokesman said Mr Salmond had failed to prove his allegations in his evidence to the committee, and “also gave testimony which directly undermined some of the central planks of his conspiracy theories”.
The inquiry is examining the Scottish government’s botched handling of harassment allegations against Mr Salmond.
The government admitted it had acted unlawfully during its investigation into the initial complaints from two female civil servants after Mr Salmond launched a judicial review case, and had to pay his legal fees of more than £500,000.
Mr Salmond was arrested two weeks after the government admitted defeat in the civil case, and was later cleared of 13 charges of sexual assault against a total of nine women after a trial at the High Court last year.
He has previously accused people close to Ms Sturgeon – his successor as both first minister and SNP leader – of plotting against him, and has named Ms Sturgeon’s husband, SNP chief executive Peter Murrell, as being one of them.
Mr Salmond told the committee that he had been given a memory stick in the build up to his criminal trial that contained messages which involved “pressuring police”, “collusion of witnesses” and “construction of evidence because police were felt to be inadequate in finding it themselves”.
He said he would “dearly love to provide” more detail about the messages – but was unable to do so because he was “under an injunction” that could see him prosecuted for revealing evidence that was given to him as part of the criminal proceedings.