Copies of a shelved report into abuse at north Wales care homes in the 1970s and 80s have been found in local council archives.
Flintshire council officials say a search has uncovered the 1996 Jillings report, which remained unpublished.
The document is a key factor in the row over abuse which has engulfed the BBC.
The six north Wales councils are now taking legal advice about whether it can be made available under Freedom of Information legislation.
It was commissioned after claims of widespread abuse in 40 homes.
Initially seven care workers were convicted in 1991 following allegations of historic abuse centring on the Bryn Estyn home in Wrexham.
However as further claims involving many more homes emerged, the former Clwyd County Council commissioned John Jillings to investigate in 1994.
Mr Jillings said his report was not published because council insurers felt it could lead to the authority being sued, and after taking legal advice it was considered the report was not suitable for publication.
A three-year inquiry conducted by High Court judge Sir Ronald Waterhouse concluded in 2000 with a report entitled Lost in Care.
Then two weeks ago, former Bryn Estyn resident Steve Messham said the full scale of the abuse was not uncovered by the Waterhouse report.
A Newsnight programme which aired on 2 November reported Mr Messham saying that a Conservative politician from the Thatcher era abused him a number of times.
Although not named by the programme, this led to incorrect speculation on the internet that the man in question was former Tory treasurer Lord McAlpine. The peer denied the reports describing them "wholly false and seriously defamatory".
Mr Messham later said police at the time had showed him a picture of his abuser but incorrectly told him the man was Lord McAlpine.
The BBC issued an unreserved apology for the Newsnight report which led to Lord McAlpine being wrongly implicated in the alleged abuse and announced an "immediate pause" in all Newsnight investigations.
Director General George Entwistle resigned on Saturday as a result of the Newsnight error.
An inquiry by the National Crime Agency is now being held into abuse claims from the 70s and 80s, fresh allegations of which have been made relating to the period and how the police handled claims made at the time.
In a joint statement on behalf of the six councils which succeeded Clwyd and the old Gwynedd council, Flintshire's chief executive Colin Everett said: "We have now established that several copies of the report are in existence in local authority archives.
"The report and any supporting documents held in archive are being made available to North Wales Police and the National Crime Agency (NCA).
"The Jillings report was disclosed to the subsequent Waterhouse inquiry and we would expect the NCA to have access to it through recovery of the papers from the inquiry, held in archive by government departments.
"North Wales local authorities are taking collective and independent legal advice on whether the report can or should be disclosed under the Freedom of Information legislation, whether in full or in part.
"The National Crime Agency is being consulted, as any public disclosure cannot compromise or prejudice the new investigation."