Nicola Sturgeon has vowed to 'fully cooperate' with police after the arrest of her husband, the SNP’s former chief executive, during an investigation into party finances.In her first public comments since Peter Murrell’s arrest, former first minister Ms Sturgeon said recent days had been "obviously difficult" as she gave a short statement outside the couple’s Glasgow home on Saturday.The former SNP leader said she could not comment on the investigation into the spending of around £600,000 which was earmarked for an independence campaign, "as much as there are things I may want to say".