ON Wednesday morning an email dropped into journalists’ inboxes across Scotland. “Police Scotland: Investigation into Scottish National Party funding and finances – man arrested,” its subject line read.

That would be enough to catch anyone’s eye. But it was the note at the email’s end that contained the true bombshell. The 58-year-old man arrested was Peter Murrell, the former SNP chief executive.

Murrell had served at the top of the party since 1999, and had only stepped down a matter of weeks earlier, ostensibly for a different matter. As such, his arrest came as a surprise to just about everyone.

READ MORE: Contempt of Court: Why the media has to be careful as police probe SNP HQ

The SNP headquarters would soon be subjected to an intense police search, as would Murrell’s house in Uddingston, which he shares with his wife the former SNP first minister Nicola Sturgeon.

One source suggested there may have been knowledge of the investigation’s progress among the most senior figures in the SNP, hinting that it may have played a role in Sturgeon’s shock decision to resign in February.

“I consider it highly likely that [Sturgeon] knew this was going to occur,” they said.

The National:

The idea that foreknowledge of Murrell’s arrest had been the “real reason” behind Sturgeon resignation was dismissed by First Minister Humza Yousaf (above), who said her record and legacy will stand on their own.

But whether Sturgeon’s legacy can survive intact is yet to be seen, especially with the party’s grassroots members said to be feeling “so shocked and so dismayed” at the arrest.

“It is the army of SNP supporters out in the wind and rain trying to get the SNP elected … How let down they must be feeling. That kind of sentiment must be expressed,” one source told The National.

There were also suggestions that the “shock, dismay, anger” among the SNP grassroots would be more widely felt, and could damage the independence cause in the polls. But this was not a universal feeling among party figures.

“The Union didn’t end when Jeffrey Archer was arrested, or when Tony Blair was questioned under caution by the police,” one source said.

No one is really sure what the findings of the probe – or its ultimate impact – will be.

As one SNP figure told The National: “We await to see what exactly this is all about.”