The husband of former Scottish leader Nicola Sturgeon was held by police last month as part of an investigation into the funding of the pro-independence SNP, which runs Scotland's semi-autonomous government, before being released without charge.

The party's treasurer has stepped back as police look into what happened to more than 600,000 pounds ($750,000) raised by Scottish independence campaigners in 2017, which was supposed to have been ring-fenced but may have been used for other purposes.

After a months-long search, SNP leader Humza Yousaf said that the party had appointed AMS Accountants Group as auditors, following the resignation of the previous auditors last year.

The party faces the prospect of a fine if it misses July deadline to file its 2022 accounts with the Electoral Commission.

"It is welcome news that AMS Accountants Group will complete the accounts for both the party and the SNP Westminster group," Yousaf said.

"There is hard work ahead, but it is really encouraging to have them on board as we work towards challenging deadlines."

Yousaf became SNP leader and Scotland's first minister in March, after Sturgeon's surprise resignation.

(Reporting by Alistair Smout)