Former Scottish First Minister Nicola Sturgeon said on Sunday she was innocent after being arrested and held for more than seven hours as part of a police probe into the fate of funds for her pro-independence Scottish National Party.
The police investigation is looking at what happened to more than £600,000 (AED 2.7 million) in funding raised by Scottish independence campaigners in 2017 which was supposed to have been ring-fenced, but may have been used for other purposes.
The arrest is deeply embarrassing for the SNP, which has dominated Scottish politics for most of the last two decades. Sturgeon stood down earlier this year, and support for the party and its aim of independence has since dropped.
"To find myself in the situation I did today when I am certain I have committed no offence is both a shock and deeply distressing... I would never do anything to harm either the SNP or the country," she said in a statement posted on Twitter.
"Given the nature of this process, I cannot go into detail. However, I do wish to say this... I know beyond doubt that I am in fact innocent of any wrongdoing."
Earlier a spokesperson for Sturgeon said she had by arrangement attended an interview with Police Scotland to be arrested and questioned, and was cooperating with the investigation.
Police Scotland said a 52-year-old woman had been arrested at 10:09 am (0909 GMT) as a suspect in connection with its probe into the SNP's finances, before being released without charge at 5:24 pm pending further investigation.
"As the investigation is ongoing, we are unable to comment further," Police Scotland said.
The SNP said it had been cooperating with the investigation and would continue to do so. "It is not appropriate to publicly address any issues while that investigation is ongoing," a spokesperson said.
In April, Sturgeon's husband Peter Murrell and the party's then treasurer Colin Beattie were both arrested and then released without charge pending further investigation as part of the same probe. Sturgeon, Murrell and Beattie were all signatories on the SNP's accounts.
At 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.