Peter Murrell, the husband of Nicola Sturgeon, who recently resigned as leader of the pro-independence SNP and as 'first minister' of Scotland, was arrested in the context of the investigations into the party's finances.
Murrell, 58, left the Scottish independence party's top administration after nearly 25 years in office, and had been much criticized for his internal management of the SNP.
Police Scotland carried out several searches of the couple's home in Glasgow and the party headquarters in Edinburgh.
The news comes less than a week after the election of Humza Yousef as the new leader of the pro-independence group and first minister of Edinburgh, following the sensational resignation of Sturgeon.
Questions had recently been raised about Murrell regarding the
alleged disappearance of £600,000 of donations to the SNP and a loan of over £100,000.
Sturgeon's husband had left his post after the controversy over the loss of 30,000 members in one year, which the party had initially denied.
The controversy had contributed to the climate of internal tension in which the election to find Sturgeon's successor had taken place.
The Murell case only exacerbates the moment of crisis of the pro-independence team, marked by a decline of the party in the polls while the percentage of Scottish people in favor of secession from the United Kingdom has dropped sharply (to 39%).