The chairman of a tribunal into the IRA murder of two senior RUC officers has written to the Irish government to raise concern at the inquiry's remit.
Harry Breen and Bob Buchanan were shot dead on their way back from a meeting with Gardai in Dundalk in 1989.
The Irish government wants to set a November deadline for the tribunal's final report. Public hearings have not yet started.
It is understood the tribunal chairman is concerned about the deadline.
The solicitor for Chief Superintendent Breen's family said the concerns must be taken seriously.
"I think it would be enormously discourteous for the Department of Justice, for the minister responsible for that department, and for the wider cabinet in fact, to ignore concerns expressed by Judge (Peter) Smithwick," he said.