The Crown Office in Edinburgh has confirmed that an inquiry into the council's involvement in SSG Seafoods was continuing.
Council staff and people in Shetland's seafood industry are understood to have made statements to the police as part of the investigation.
A Crown Office spokeswoman said: "We have received a report and there is an ongoing investigation into it at the moment."
The news comes in the wake of the SIC's chief executive Morgan Goodlad being reprimanded by the Scottish Local Authority Ombudsman for his involvement in advising on £1 million of assistance to the firm.
In May the ombudsman found Mr Goodlad guilty of maladministration for failing to declare an interest when advising Shetland Development Trust on the investment which helped SSG buy Dury Salmon, a local firm, in 2002. The ombudsman said she did not believe Mr Goodlad's claim that he was not aware that his brother Alistair was chairman of SSG Seafoods when the assistance was discussed. Alistair Goodlad was also an SIC councillor at the time.
Last month Shetland's 22 councillors backed a motion giving their support to the chief executive after hearing a report on the matter from the SIC's chief legal officer Jan Riise.
SSG Seafoods went into liquidation in December 2003 during the middle of a salmon industry crisis caused by a price collapse. The business had been set up in early 2000 when several independent Shetland fish farmers joined forces to rear salmon through a contract growing arrangement.
Initially Shetland Leasing and Property (SLAP), a company owned by Shetland Charitable Trust, provided working capital of £1.5 million. However the company found itself in difficulty and Shetland Development Trust invested £500,000 in shares and stumped up a £750,000 loan in 2002.
The following year the trust signed a £3.5 million guarantee to feed supplier Skretting as well as a £900,000 loan guarantee to the Royal Bank of Scotland, who eventually pulled the plug on the business.
The total amount of public money which had been invested in the firm was £7.8 million. The collapse caused an outcry throughout Shetland with two complaints being made to the Standards Commission and a petition signed by 10 per cent of Shetland's population demanding the council investigate the matter.
Soure: The Shetland News