Reams of police documents linked to a suspect in the loyalist murder of a GAA official have been found during the closure of a PSNI station, a coroner has been told.
The files relating to the suspect in Sean Brown's killing in 1997 were discovered while an inventory was being taken of the contents of Maghera station.
The files focus on a separate money laundering investigation in which the unnamed individual was also a suspect.
The revelation in a case already steeped in controversy emerged during a preliminary inquest hearing in Belfast.
Counsel representing senior coroner John Leckey told him the information could be potentially relevant to the long-delayed inquest for Mr Brown.
Gerry McAlinden QC warned that the need to pore over the "voluminous" documentation to assess its significance could prompt a further delay to the start date of the full inquest.
"We can't really set a commencement date for this inquest in the near future," he said.
Mr Brown, 61, was abducted and killed as he closed the gates of a GAA club in Bellaghy, Co Londonderry.
Solicitor Niall Murphy, representing the Brown family, said he had "grave concerns" over the emergence of the files at such a late stage of the preliminary inquest process.
Mr Murphy said the Brown family had already shown great patience in the nine years since the inquest started.
He told Mr Leckey that today's preliminary hearing was the 25th in the case.
"To be advised so late in the day that volumes of material potentially pertinent to a suspect has been 'found' - and I respectfully insert the inverted commas - is a matter of grave concern," he said.
An earlier hearing was told that a long undisclosed review of the original Royal Ulster Constabulary (RUC) murder probe by the PSNI's now defunct Historical Enquiries Team (HET) contained damning criticism.
After a protracted process, the HET document was finally disclosed by police to parties involved in the inquest in February.
Mr Murphy revealed today that HET investigators had found that some RUC reports on an individual named as "Suspect 5" had been classified by commanders as "Not for downward dissemination".
The solicitor said this meant the documents were not shared with officers investigating the murder.
He said the coroner needed to know whether Suspect 5 was the same suspect referred to in the money laundering investigation documents.
Mr Murphy told Mr Leckey that if there had not been extensive delays in the PSNI disclosing documents to the court, the inquest may have already been heard without ever knowing of the new files.
"This inquest would have commenced and you wouldn't have been privy to the potential relevance to this voluminous material that has been found in Maghera and that's a matter of grave concern," he said.
Mr McAlinden earlier told the court much of the documentation contained evidence of a financial nature.
He suggested to Mr Leckey that might further extend the time required to study the files.
"In order to ensure that all relevant material is before this court when this inquest commences it is important for your counsel at this stage to inspect the documents collated during this money laundering investigation to ascertain whether there is any relevant documentation that relates to the Sean Brown killing," he said.
Mr McAlinden said he would start examining the papers next week.
"It may take some considerable time to process the documents and digest their contents to take a determination whether they're relevant," he said.
The barrister added: "I realise this is an unsatisfactory situation but counsel needs to ensure no stone is left unturned."
Martin Wolfe QC, representing the PSNI, said Mr McAlinden had outlined a "prudent and constructive way forward".
He said it was important to distinguish the murder case files from the money laundering documents and stressed that the PSNI had already taken steps to disclose the murder probe papers to the court.
Mr Leckey scheduled another preliminary hearing for next month.
After the hearing, a PSNI spokeswoman said: "The materials held at Maghera station relate to an ancillary money laundering inquiry, separate and distinct from the Sean Brown murder investigation.
"In compliance with its ongoing statutory disclosure duty, PSNI informed the coroner of the money laundering investigation materials, alerted him to the limited crossover of persons of interest and invited him to view same in order to determine the relevance or otherwise of the material to the inquest into the death of Sean Brown.
"PSNI have arranged for counsel to the coroner to commence consideration of the money laundering materials at 9.00am on Tuesday 21st April 2015."