Claims that two police intelligence officers visited a dissident republican in custody hours before he killed himself must be investigated before an inquest can be held, a coroner has said.
The probe into the suicide of John Brady, 40, inside Strand Road police station in Londonderry in October 2009 had been due to be heard early next month, but Northern Ireland's Senior Coroner John Leckey said the need to examine the allegation could now see the inquest delayed by at least a year.
At a preliminary hearing in Belfast, a representative for the Police Ombudsman confirmed that officers from the PSNI's C3 unit - formerly known as Special Branch - had attended the station's custody suite on the day, but said there was no evidence they had contact with Mr Brady.
The issue was raised after a solicitor representing Mr Brady at the time of his death - John Finucane - wrote to the coroner to relay a claim made to him that intelligence branch officers had seen his client.
Rumours of C3 involvement has led to speculation the republican may have been subjected to a bid to turn him into an informer before he hanged himself in a consultation room
Brady, who was jailed during the Troubles for murdering a policeman, had been arrested in Strabane while on parole on suspicion of assault.
Mr Finucane told Mr Leckey that he was made aware of the claim when he attended a subsequent police disciplinary hearing which related to his client's care in custody.
He said the issue had been touched upon by the disciplinary panel, which was examining whether appropriate steps had been taken to prevent his suicide, but that someone then spoke to him more fully about it on the margins of the hearing.
But he told the court he could not recall who specifically had raised the issue with him.
Noting that the alleged contact happened at a time when he was not in the custody suite, Mr Finucane added: " I am reporting what's been said to me. In regard to whether it happened or not, I can't be of assistance with that."
Philip McAteer, representing the PSNI, acknowledged the claim was a serious matter and stressed the need to establish the facts before the inquest proceeded.
"This could be an example of a conspiracy theory that has developed at some stage," he said.
The lawyer expressed concern that unverified claims could be raised during the inquest.
He added: "Especially in cases with a jury, the last thing we want is this being thrown out there and left hanging because of the seriousness of the implications."
Paul Holmes, representing Police Ombudsman Michael McGuire, confirmed that C3 officers had been in the Strand Road facility on the day.
"C3 did attend the custody suite but there is no evidence that they actually had contact with Mr Brady," he said.
Mr Leckey asked that all the proceedings of the police's disciplinary hearing were transcribed so the court could examine them for potential references to the incident.
He also accepted an offer from Mr Holmes to interview the individuals who had attended the disciplinary session.
Noting that the transcription would take four weeks, Mr Leckey conceded the scheduled start date of November 5 would be missed.
Explaining that his diary was full for at least the next 12 months, he warned that the inquest could be subject to delay, barring a hitch to another scheduled inquest.
"I have no availability for a year, that's the reality," he said.