Police have arrested the husband of former Scottish first minister Nicola Sturgeon as a suspect in an investigation into the funding and finances of the Scottish National party.

Peter Murrell resigned as chief executive of the SNP last month after the party was forced to admit it had 30,000 fewer members than it had claimed. Murrell had served as chief executive since 1999 and in 2010 married Sturgeon, who stepped down as first minister last week.

Police Scotland, the national force, said it had arrested a 58-year-old man on Wednesday and that he was in custody and being questioned by detectives.

“Officers are also carrying out searches at a number of addresses as part of the investigation,” the force said in a statement. A person familiar with the situation confirmed BBC reports that Murrell was the arrested man.