The SNP is deeply riven by ideological and political disputes. Its membership has fallen by 30% over the last year. Peter Murrell's arrest is likely to have a far-reaching effect on the party. These may include denting Sturgeon's successor's attempts to rebuild the party's support base, rebuilding finances, and facing stiff competition from Labour — who are now winning support from pro-UK and pro-independence voters.
The SNP's finances were the reason for Sturgeon's resignation — not the "physical and mental impact" of dealing with COVID. It is clear Murrell's impending arrest would’ve been awkward for her if she were still in office. Whether or not she was involved in the mishandling of funds is yet to be known, but the power couple has much to explain.