Nicola Sturgeon’s husband, Peter Murrell, is understood to have been arrested in connection with an investigation into the funding and finances of the Scottish National Party (SNP).
The former SNP chief executive is in custody and is being questioned by detectives.
Police Scotland said a 58-year-old man was arrested as part of an ongoing investigation.
Officers are also carrying out searches at a number of addresses, the force added.
A spokesperson for the Crown Office and Procurator Fiscal Service said: “COPFS will continue to work with police in this ongoing investigation.
“It is standard practice that any case regarding politicians is dealt with by prosecutors without the involvement of the Law Officers.”
It comes less than a week after Humza Yousaf was legally sworn in as Scotland’s sixth first minister – replacing Sturgeon after her shock resignation in February.
Mr Murrell stepped down as SNP chief executive during the recent leadership campaign.
