Nicola Sturgeon's husband, Peter Murrell, has been arrested by Police Scotland in an investigation into the SNP's finances.
The 58-year-old was the party's chief executive until just last month.
Police Scotland and the Crown Office are investigating how £600,000 in donations to the SNP were spent.
A Police Scotland statement said: “A 58-year-old man has today, Wednesday, 5 April 2023, been arrested as a suspect in connection with the ongoing investigation into the funding and finances of the Scottish National Party.
“The man is in custody and is being questioned by Police Scotland detectives.
“Officers are also carrying out searches at a number of addresses as part of the investigation.
“A report will be sent to the Crown Office and Procurator Fiscal Service.
“The matter is active for the purposes of the Contempt of Court Act 1981 and the public are therefore advised to exercise caution if discussing it on social media.
Peter Murrell stood down from his position as chief executive last month
PA
“As the investigation is ongoing we are unable to comment further.”
Officers are also carrying out searches at a number of addresses as part of the investigation.
Murrell quit his role as chief executive during the leadership race to replace his wife as SNP leader, claiming he had become a "distraction" to the contest.
There had been questions over his management of the party, on top of the ongoing police investigation into the SNP's finances, there was anger after journalists were provided with bogus membership numbers.
The SNP's head of communications denied reports that the SNP had lost 30,000 members branding them "inaccurate" and "drivel".
Standing down from his role on march 18, Murrell said: "Responsibility for the SNP's responses to media queries about our membership number lies with me as chief executive.
Police have raided several properties as part of the investigation
PA
"While there was no intent to mislead, I accept that this has been the outcome. I have therefore decided to confirm my intention to step down as chief executive with immediate effect.
"I had not planned to confirm this decision until after the leadership election.
"However, as my future has become a distraction from the campaign I have concluded that I should stand down now, so the party can focus fully on issues about Scotland's future.
"The election contest is being run by the national secretary and I have had no role in it at any point."