Police have launched a probe into alleged leaked documents which suggest Nicola Sturgeon’s husband appeared to back police action against Alex Salmond.

The Crown Office instructed officers to investigate how WhatsApp messages appearing to show SNP chief executive Peter Murrell calling for pressure to be put on the police over the Salmond case were made public.

Another message appears to show Murrell supporting action by prosecutors in relation to the former first minister.

The wording of the messages can be revealed today.

Earlier this week, The Record revealed senior SNP MP Kenny MacAskill had demanded an investigation after being anonymously passed a document relating to the messages.

MacAskill passed the information to a Holyrood committee that is investigating the Salmond controversy, as well as to the Crown Office.

The first message states: “Totally agree folk should be asking the police questions…..report now with the PF on charges which leaves police twiddling their thumbs. So good time to be pressurising them. Would be good to know Met looking at events in London.”

The second message states: “TBH the more fronts he is having to firefight on the better for all complainers. so CPS action would be a good thing.”

Alex Salmond with Kenny MacAskill in 2011

Now Police Scotland has been instructed to open an inquiry into 'unlawful disclosure of material' following the bombshell revelations.

Salmond was acquitted of sexual offences charges at a criminal trial earlier this year.

A Police Scotland spokesperson said: "The Crown Office and Procurator Fiscal Service has instructed us to investigate the potential unlawful disclosure of material.

"Enquiries are at an early stage.”

MSPs are examining the Scottish Government’s botched handling of sexual misconduct allegations against Salmond when he was first minister.

The former SNP leader took civil legal action against the Government and it was agreed the internal probe had been unlawful and tainted by apparent bias.

The initial Government probe is said to have destroyed the friendship between Sturgeon and Salmond, whose allies believe he has been the victim of a conspiracy.

MacAskill, a Salmond ally who is now the SNP MP for East Lothian, told the Daily Record he received an anonymous document recently.

It claims to show WhatsApp messages by Murrell in January 2019, after Salmond had appeared in court charged with sexual offences.

It was also the month in which a separate complaint was made about Salmond to the Metropolitan Police, an investigation the London force later dropped.

MacAskill said: “I can confirm that I received an anonymous letter containing a document. I have notified both Alex Salmond and the Crown and have passed it to the inquiry committee at the Scottish Parliament.

“I would like the Scottish Parliament and the Crown Office to investigate the contents of this document.”

Labour MSP Jackie Baillie followed MacAskill's calls by urging Murrell to provide “full transparency” over the WhatsApp messages claim.

Baillie, who sits on the Holyrood committee examining the bungled probe, said: “While the committee is used to secrecy on the part of the SNP Government, it appears from these latest revelations, if true, that the SNP chief executive has questions to answer.

Nicola Sturgeon with husband and SNP chief executive Peter Murell

“We expect full transparency from Mr Murrell when he appears before the committee.”

Murrell is the long-standing CEO of the SNP and held the job before his wife became party leader.

MacAskill used to be close politically to Sturgeon, but they fell out when he left her Government in 2014.

In a recent article, he claimed “dark forces” were behind the prosecution of Salmond, adding: “As a defence agent of 20 years’ standing and a former justice secretary, I’ve known major police inquiries but never of such magnitude other than for the most heinous of crimes and dangerous of offenders.”

Murrell, the second most powerful person in the SNP after his wife, was contacted by the Holyrood committee about his knowledge of the complaints to the Government about Salmond.

He was also asked about what action was taken at a party level about the complaints. The committee has since asked him for more information.

The SNP have been contacted for comment by the Daily Record.

A Police Scotland spokesperson said: "The Crown Office and Procurator Fiscal Service has instructed us to investigate the potential unlawful disclosure of material. Enquiries are at an early stage."