The Audit Commission report that urged the move was sent to the council's former director of finance, Donald Macleod, and his former deputy, Brian Lawrie, yesterday.
The commission has the power to recommend to the Secretary of State for Scotland that a surcharge be imposed on officals and councillors for loss of the money.
The commission's three-day inquiry, in Stornoway in March, followed the report last October by the Controller of Audit, John Broadfoot.
He found that pounds 16m had been borrowed before the need to invest, and targeted three officials for negligence - Mr Macleod, who was sacked and has since left the island, Mr Lawrie, who was due to leave anyway for another job, and Brian Rattray, the assistant director of finance, who is still with the council. Mr Broadfoot said the officials had made a distinction between 'borrowing and lending' and the illegal practice of 'borrowing to on-lend'.
The council chief executive, Dr George Macleod, who was sacked and then reinstated, has since had his second request for early retirement approved.
The council said yesterday it was considering the Audit Commission findings.
BCCI law battle, page 20