He should resign verbally but not formally go until a new FM has been elected by the SNP membership.
The notion that he could resign and Neil Gray steps in unelected is just nonsense.
Some of the tweets are the usual shite about the Lord Advocate and the Solicitor General despite the fact that all of Scotland’s prosecutors act independently of political interference. It is standard practice that any case regarding politicians is dealt with by prosecutors without the involvement of the Lord Advocate or Solicitor General.
As for those accusing Police Scotland of being corrupted by the SNP - that's on a level with the MI5 conspiracy theorists in the other camp.