Peter Murrell’s £400,000 SNP spending spree was exposed after detectives uncovered his ‘outrageous’ splurges on Montblanc pens and Le Creuset cookware using the party card.Officers grew suspicious when they found large sums of SNP funds had been spent on luxury lifestyle items, despite the its strained finances.After Murrell was jailed for five years and three months today, Police Scotland released interview footage showing the former SNP chief executive sitting silently and expressionless as he was questioned about the spending.One detective told him: ‘Over £19,000 is exclusively on pens alone. It’s quite frankly an outrageous amount of money to be spending on pens, in my opinion… What does the SNP need over £19,000 of luxury pens for?’Murrell stared back but refused to answer as he was accused of ‘thieving’ £400,000 from SNP members.It came as his estranged wife Nicola Sturgeon, through her lawyer, insisted she is ‘innocent of any crime’ and hit out at ‘anonymous sources’ attempting to ‘insinuate guilt’ on her part.Scotland First Minister John Swinney said the Peter Murrell saga had been ‘agony’ as his party’s former chief executive began his jail term.Murrell’s world – and his marriage – began to unravel when detectives identified suspicious purchases, including Le Creuset Mickey Mouse ramekins and a ‘steel zen tea kettle’, on the SNP's card, with no record of them in the party’s accounts.Expenditure which should have been logged in the SNP's accounting system, but were missing, raised alarm bells, strengthening suspicions of criminality at the heart of the party, then led by Murrell’s wife.The spending trail led investigators to Murrell and this marked the start of a downfall that culminated today in his five-year prison sentence.Ms Sturgeon’s estranged husband had stubbornly refused to answer questions as detectives grilled him over the embezzlement – including what he would say to party members whose money had been stolen.He also remained silent when asked about his apparent Amazon habit and why so much had been spent on luxury pens, including Montblanc sets, for a party campaigning for Scottish independence.