A senior Sinn Fein Assembly member may be called to give evidence at the inquest of Gareth O'Connor, a coroners court has heard.
Gerry Kelly may be asked to explain what, if any, inquiries he made about alleged Provisional IRA involvement in the murder of the father of two more than a decade ago.
The revelation came just hours after it emerged that Martin McGuinness has agreed to appear at a separate inquest about IRA activities during the height of the Troubles.
Mr O'Connor, 24, disappeared near the Irish border in 2003 on his way to sign bail on a charge of Real IRA membership. His body was found two years later in a car pulled from the Newry canal. No one has ever been convicted in relation to his death.
His family allege he was killed by the PIRA - a claim the organisation denied at the time he vanished.
A preliminary hearing at Belfast's Laganside Court was told that the victim's father claimed Mr Kelly attended their house on two occasions and offered assurances that the PIRA was not involved in the killing.
Gerry McAlinden, counsel for the Coroners Service, said: "It would appear that if he (Mr Kelly) did what he is alleged to have done, he did carry out some investigations and came back to the family.
"It may be relevant to ascertain from him the nature of those inquiries or investigations especially where the family are convinced the Provisional IRA were involved."
An inquest for Mr O'Connor was dramatically halted last year when it emerged the murder suspect had mistakenly been issued with a so-called "on the run letter".
Mr Kelly had been the "postman" for the document which stated that the individual was no longer wanted, the court was told.
The inquest was stopped to allow police to assess whether a prosecution was possible after the Government announced it would no longer stand over the letters of comfort.
Mr Kelly, an MLA for North Belfast, has not yet been formally approached by the Coroner's Service, it was claimed.
Mr McAlinden added: "Mr Kelly's solicitor wrote to the Coroners Service after the previous hearing and expressed great displeasure at his name being mentioned in the context of the inquest.
"He was frankly quite annoyed that he had been dragged into this at this stage."
Meanwhile, it also emerged that police have not yet questioned the murder suspect, who lives in the Republic of Ireland.
A barrister for the Police Service of Northern Ireland said officers were liaising with their counterparts in An Garda Siochana.
Mark Robinson said there was "no timescale" for ascertaining when an interview may take place.
Mr McAlinden said: "Every opportunity should be grasped by the PSNI and every effort made to bring individuals to justice."
The case is among 56 long running legacy inquests being reviewed by Lord Justice Weir.
The OTR scheme came to public prominence in 2014 after the prosecution of a man for the murder of four soldiers in an IRA bombing in Hyde Park in 1982 was halted when it emerged he received one of the letters in error when he was in fact wanted by the Metropolitan Police.
Co Donegal man John Downey, 63, who denied involvement in the bomb, walked free from the Old Bailey when the judge ruled that his arrest had been an abuse of process.
Around 200 letters were issued to individuals under the Government scheme, with Sinn Fein acting as the conduit in many of the cases.
A review into the process ordered by Prime Minister David Cameron and conducted by Lady Justice Heather Hallett identified other instances where errors may have been made.
The suspect in the O'Connor case was revealed as one of those cases.