The family of missing teenager Arlene Arkinson is deeply frustrated by delays in concluding a long-running inquest, a coroner's court has heard.
Criticism was aimed at authorities in Dublin which have failed to hand over documentation about Garda investigations into the schoolgirl's disappearance over 20 years ago.
Barrister Ivor McAteer said: "The family is deeply frustrated and they are becoming more and more upset as time goes on at the thought this might falter at the final hurdle."
However, the lawyer tempered his remarks because senior counsel had now been appointed to oversee the disclosure process in Dublin.
"I will reserve any further comment," he added.
Arlene (15) from Castlederg in Co Tyrone, vanished after a night out across the Irish border in Co Donegal in August 1994.
She was last seen being driven down a country road by convicted paedophile and child killer Robert Howard.
He was acquitted of her murder in 2005 by a jury not told of his lengthy criminal past which included the murder of South London teenager Hannah Williams several years earlier.
A preliminary hearing at Belfast's Laganside Court was told that despite ongoing and active correspondence information has not yet been shared by authorities in the Republic of Ireland.
In September, representatives for Coroner Judge Brian Sherrard met with officials from the Chief State Solicitor's Office and An Garda Siochana in Dublin to discuss the case.
Emails and letters have also been sent and telephone calls made, the court was told.
While sharing frustration at the length of time taken to disclose material, Judge Sherrard said he was assured the matter was being progressed.
He said: "We are in a process and I think am encouraged by what I have heard and reassured that the State Solicitor's Office is taking this matter forward with consciousness.
"Nevertheless, I think it is important that we all try to keep an overview on this and do not allow this matter to slip."
A further preliminary hearing has been scheduled for December 21.
