The public inquiry into the loyalist murder of solicitor Rosemary Nelson in 1999 is to be delayed by a year, with officials signalling that they underestimated the scale of the task.
The inquiry team probing allegations of security force collusion in the killing began its work in April and hoped to start public hearings into the high-profile murder by the beginning of next year.
But yesterday (Wednesday) it issued a statement revealing that the "complexity of the issues" and the volume of material had forced a delay until January 2007.
Colm Owens, solicitor for Mrs Nelson's mother Sheila Magee, said the family had recently been told the inquiry start-date was likely to slip from the spring of next year until the autumn.
Noting that the decision to set up the inquiry was announced in November 2004, he said: "We already expressed our disappointment when it was indicated that it would not start in the spring of '06. This has come as a further hammer-blow."
London-based human rights group British Irish Rights Watch has been closely associated with Mrs Nelson's case.
Its director, Jane Winter, said the priority must be a thorough investigation.
"Although a further delay is obviously disappointing for the family, we think it is important that this inquiry is done well, rather than done quickly," she said.
News of the delay is the latest development in a long-running controversy, the origins of which pre-date Mrs Nelson's tragic death.
Rosemary Nelson, a 40-year-old mother-of-three who ran her own legal practice in Lurgan, Co Armagh, became involved in a number of high-profile cases in the mid-1990s.
She was killed on March 15 1999 when a bomb exploded beneath her car as she drove to work.
Prior to her death she alleged that her life was threatened by members of the security forces, with RUC officers accused of making threats against her while interviewing her clients.
Her complaints attracted widespread media attention when she brought them before a committee of the US Congress.
The prominence of her case failed to deter her killers. The attack was claimed by the loyalist splinter group the Red Hand Defenders.
But Mrs Nelson's allegations of police harassment ensured there were immediate allegations of security force collusion in the killing.
Her murder came two days before St Patrick's Day and increased tensions at a sensitive time.
Northern Ireland's political leaders were in Washington on the day of the murder amid intense attempts to implement the Good Friday Agreement signed a year earlier.
Mrs Nelson was legal representative for the Garvaghy Road residents' group and had become a hate figure among loyalists who supported the Orange Order's Drumcree marching protest.
She also represented relatives of murdered Portadown Catholic Robert Hamill, killed by a loyalist mob while RUC officers were in the area.
Another of her clients was Lurgan republican Colin Duffy who was cleared of the murder of a soldier after it emerged that a key police witness was a loyalist paramilitary.
Calls for an independent inquiry in the immediate aftermath of her death were refused despite an international campaign and the support of notable United Nations figures.
A police investigation led by Norfolk deputy chief constable Colin Port, but which maintained a RUC element, spent millions of pounds in a major murder hunt but failed to charge anyone.
Four loyalists are currently facing serious charges based on evidence gathered by the Port team, although these are all unrelated to Mrs Nelson's case.
In the wake of the failed police probe Mrs Nelson's murder figured among a number of cases reviewed by retired Canadian judge Peter Cory.
Mr Cory recommended Mrs Nelson's case for public inquiry.
He made similar recommendations over the murder of Robert Hamill, Belfast solicitor Pat Finucane, loyalist paramilitary leader Billy Wright, and the IRA killings of two senior RUC officers.
The Rosemary Nelson Inquiry held a preliminary hearing on April 19 this year and predicted that its hearings, when witnesses would testify in public, would begin in spring 2006.
A statement issued by the inquiry yesterday pointed out that since April it had recruited solicitors to gather witness statements and selected a team of former police officers to review the Port investigation.
It added: "In the course of the nearly eight months of work which the inquiry has undertaken since the opening hearing, there has been a marked increase in the complexity of the issues which the inquiry will have to consider within its terms of reference and in the amount and range of the documentation and other material pertaining to those issues which has been disclosed to the inquiry."
It said that as a result it was now apparent that the inquiry would "need to obtain witness statements from several hundred witnesses".
"Secondly, the process of analysing and ordering the material disclosed to it and of assessing the implications for the inquiry and others of that part of the disclosed material which is sensitive, has proved to be a huge and continuing task," the statement said
It continued: "It is clear to the inquiry that it will not be possible to begin its full hearings in the spring of next year."
Estimating that the task would "require a further year of hard work", it added: "The inquiry believes that there is merit in fixing a date for the start of the full hearings at this stage.
"This will help to focus the efforts of all those who are involved in or affected by the work of the inquiry. It will also assist them with their future planning and arrangements.
"The inquiry intends to begin the full hearings on Tuesday January 16 2007 in Belfast."
The inquiry team, led by retired English High Court judge Sir Michael Morland, appealed for anyone with relevant information to come forward.