Sturgeon has been arrested in connection with a police investigation into the Scottish National Party’s funding.

Former Scottish leader Nicola Sturgeon was arrested as part of an investigation into financial irregularities of the Scottish National Party (SNP). She was later released without charge pending further investigation.

“A 52-year-old woman has today … been arrested as a suspect in connection with the ongoing investigation into the funding and finances of the Scottish National Party,” Police Scotland said in a statement on Sunday, with British media confirming her identity as Sturgeon.

A spokesperson for Sturgeon said she was assisting with the police probe. “Nicola has consistently said she would cooperate with the investigation if asked and continues to do so.”

It is the third arrest in the probe, which is sending shockwaves through Scotland’s political system. Sturgeon’s husband Peter Murrell, the former chief executive of the SNP, was arrested as part of the probe in April.

Murrell has long faced questions over the alleged diversion of  600,000 British pounds ($754,000) in SNP donations that were meant to support its drive for Scottish independence.

He also failed to declare a personal loan to the SNP of more than 100,000 British pounds ($125,700), which could breach laws on political funding transparency. He was later released without charge pending further investigation.

Party treasurer Colin Beattie was also arrested in April and later released.

Sturgeon made her final appearance as first minister in the Scottish Parliament in March, having announced her intention to retire a month earlier.

‘I am a human being’

The arrest of Sturgeon is deeply embarrassing for the SNP, which campaigns to end Scotland’s three-century political union with England.

“These issues are subject to a live police investigation. The SNP have been cooperating fully with this investigation and will continue to do so, however, it is not appropriate to publicly address any issues while that investigation is ongoing,” an SNP spokesperson said.

A the time of Murrell’s arrest, police carried out a lengthy search of the couple’s home in Glasgow, which was sealed off with blue and white police tape.

Sturgeon, Scotland’s longest-serving leader of its semi-autonomous government, caught the political world by surprise when she announced her resignation in February, saying she had become too divisive to lead her country to independence.

Acknowledging the strains of office, Sturgeon said on her departure that she felt unable to give “every ounce of energy that it needs” to see out the high-pressure job.

“I am a human being as well as a politician,” she said.