The report of the three-man committee investigating allegations that gardaí had information the "Real IRA" was planning a car bomb attack before the Omagh blast is near completion.
A spokesman for the Minister for Justice said last night the report was expected to be presented to Mr McDowell before Christmas.
The former minister for justice, Mr O'Donoghue, decided to set up the inquiry earlier this year after the Police Ombudsman for Northern Ireland, Ms Nuala O'Loan, presented a report to the Minister for Foreign Affairs, Mr Brian Cowen.
That report related to allegations made by a serving Garda about the handling by the authorities of intelligence information about the activities of paramilitary groups.
Mr Cowen passed on the report to Mr O'Donoghue, who then decided to have an inquiry into the matter.
Mr O'Donoghue set up a three- man committee to carry out the inquiry into Ms Loan's report.
The committee consists of Mr Dermot Nally, former secretary to the government, Mr Eamon Barnes, former director of public prosecutions, and Mr Joe Brosnan, former secretary of the Department of Justice.
In all, 29 people and two unborn children were killed when a car bomb exploded in Omagh on August 15th, 1999.