The Lord Advocate Frank Mulholland issued his message when he appeared before the Scottish Parliament to answer questions about the Crown Office’s handling of the investigation into property transactions with links to the former SNP front-bencher.
Police Scotland has launched an investigation into the struck-off solicitor Christopher Hales, who acted for Ms Thomson in a string of deals.
Although he did not mention Ms Thomson by name, the Lord Advocate said Police Scotland would widen its investigation beyond the activities of Mr Hales if the evidence suggested others were involved in criminality.
Conservative MSP Murdo Fraser asked the Lord Advocate: “In what circumstances would the Crown Office ask Police Scotland to investigate any other person connected with the solicitor subject to the Law Society’s judgment?”
Mr Mulholland replied: “I gave some consideration to that because I think it is a highly relevant question. The referral to Police Scotland is in relation to the solicitor who was the subject of the Scottish Solicitors Disciplinary Tribunal finding and the police have been instructed to investigate the property transactions relating to that finding resulting in the solicitor being struck off.
“Police Scotland have a duty in any criminal investigation to follow the evidence and where that takes them. So if during a police investigation evidence arises that other persons have been involved in whatever crime that the police have uncovered evidence of, then I have faith in them that they will do the right thing as will the Crown.”
Ms Thomson has maintained she has always acted within the law as the spotlight has been shone on her business relationship with Mr Hales and the 13 transactions the lawyer conducted in 2010-11.
The transactions have proved deeply controversial as it emerged that properties were bought cheaply from people looking for a quick sale then sold on at an inflated price the same day.
Mr Hales was struck off by the Law Society in May last year following a tribunal which concluded that he “must have been aware that there was a possibility that he was facilitating mortgage fraud”.
Opposition politicians have questioned why a police investigation into the deals was not launched until July this year following the Law Society’s investigation into Mr Hales.
The Lord Advocate said the first time the Crown Office was made aware of the identity of Mr Hales’ clients was when the case was formally referred by the Law Society on 3 July 2015.