The PSNI is seeking to question the former IRA man turned writer, Anthony McIntyre, about his Boston College interviews with former provisionals about Jean McConville's murder.
As the interviewer for the US university's oral history project, Mr McIntyre's evidence would be crucial in the case against Ivor Bell and any other former IRA leaders who may in future be charged with involvement in the horrific 1972 abduction and killing.
The Belfast Telegraph has learned that detectives questioning Bell were "keenly interested" in Gerry Adams' alleged role in the mother-of-10's murder. The Sinn Fein president strongly denies any involvement in her death.
Belfast Magistrate's Court heard on Saturday that Bell was an interviewee in one of the tapes known as 'Man Z' which Bell denies.
The 77-year-old is charged with IRA membership and aiding and abetting the murder of Jean McConville. Other ex-IRA members are expected to be arrested in the coming weeks by detectives who have in their possession tapes of seven republicans, who are all still alive, allegedly discussing the McConville killing.
It is understood the PSNI wants to question Mr McIntyre about Bell's alleged interview, and the conditions in which it took place, in order to corroborate the claims allegedly made in the tape.
Mr McIntyre would be quizzed as to whether Bell was 'Man Z' and the validity of the recordings he made of his interviewees.
However, sources said there were "absolutely no circumstances" in which Mr McIntyre would co-operate with police. Refusal to do so could result in him facing charges of withholding information but the sources said he would "go to jail rather than compromise source protection".
Mr McIntyre is a member of the National Union of Journalists and the issue is to be raised with the union this week.
The ex-IRA man has previously said he has "every sympathy with the McConville family in their search for truth recovery but journalists, academics, and researchers need protection if they are to gain the necessary information which offers a valuable insight into the past".
As the lead researcher for the Belfast project for Boston College between 2001 and 2006, Mr McIntyre conducted over 170 interviews with 26 republicans.
They were undertaken on the agreement that the interviews wouldn't be released until after the interviewee's death.
Tapes of now deceased IRA members Dolours Price and Brendan Hughes – who both accused Gerry Adams of ordering Jean McConville's murder – were handed over to the PSNI by Boston College.
However, a major legal battle followed over the taped interviews of republicans who are still alive.
Last June, the US Court of Appeals for the First Circuit ordered that 11 interviews with seven other republicans – in which Jean McConville's murder was mentioned – be given to the PSNI.
It is understood that in these tapes, other shootings, bombings and IRA activities are discussed.
However, the US courts gave the police the tapes under the Mutual Legal Assistance Treaty (MLAT) which means that they can be used only in the Jean McConville murder inquiry and not in any other investigations.
The interviewees in Boston College's Belfast project were all given code names. The PSNI has employed voice analysis technology in its efforts to link the tape interviews to known republicans.
It is understood detectives want to ask Mr McIntyre to corroborate their efforts to identify the republicans he interviewed.
Veteran republican in custody over murder charges
The police case against a veteran republican charged in connection with the notorious IRA murder of Belfast mother-of-10 Jean McConville is based on an interview he allegedly gave to researchers at a US college, a court has heard.
The claim was made as Ivor Bell (77), was refused bail and remanded in custody by a district judge in Belfast accused of aiding and abetting in the murder as well as membership of the IRA.
Boston College interviewed a number of former paramilitaries about the Troubles on the understanding transcripts would not be published until after their deaths – but that undertaking was rendered ineffective when a US court last year ordered that the tapes be handed over to the PSNI.
The interviews included claims about the murder of Mrs McConville, who was abducted by the IRA at her home at Divis Flats, Belfast in 1972, shot dead and then secretly buried.
Applying for bail, Peter Corrigan, representing Bell, told district judge Amanda Henderson on Saturday that the prosecution case was that an interviewee on one of the Boston tapes, referred to only as 'Z', was his client.
But the solicitor insisted the person interviewed on the tape had denied any involvement in the murder.
"During those interviews 'Z' explicitly states that he was not involved with the murder of Jean McConville," he said.
Mr Corrigan also questioned the evidential value of the interviews, as they had not been conducted by trained police officers.
Grey-haired Bell, from Ramoan Gardens in the Andersonstown area of west Belfast, sat impassively in the dock as his lawyer made the claims.
Some of Mrs McConville's children watched from the gallery.
A PSNI detective inspector, who earlier told the judge he could connect the accused with the charges, rejected Mr Corrigan's interpretation of the Boston College interview.
The officer said he opposed bail on the ground that the defendant would likely flee the jurisdiction.
But Mr Corrigan said that was out of the question, noting that his client suffered from a range of serious medical conditions and that his family was based in Belfast.
Judge Henderson said she was more convinced with the argument the prosecution had made.
Bell was remanded in custody to appear before court again next month.
After the hearing, Mrs McConville's son Michael said the family's thoughts were with their mother.
"The pain of losing her has not diminished over the decades since she was taken from us, murdered, and secretly buried," he said.
Four decades of a family's search for truth and justice
May 1972: Jean McConville, a widowed mother-of-10, was dragged away from her children at their home in west Belfast's Divis flats by an IRA gang of up to 12 men and women after being accused of passing information to the Army in Belfast.
1999: After a group is set up to find the Disappeared, the IRA finally admits Mrs McConville was murdered.
Information is passed on to Gardai.
However, republicans secure legal guarantees that mean evidence given to the Independent Commission for the Location of Victims Remains is inadmissible in criminal proceedings.
August 2003: After several failed attempts to locate her remains, Mrs McConville's remains are finally found on Shelling Hill beach, Co Louth.
March 2010: Sinn Fein president Gerry Adams is accused by the late Belfast IRA commander Brendan 'Darkie' Hughes of setting up a secret unit that abducted Mrs McConville from her home and "disappeared" her, through a series of interviews for the Boston College Belfast Project.
February 2011: Mrs McConville's family members visit the Louth constituency where Mr Adams is standing for election to urge voters to reject his election campaign.
Mr Adams strongly denies any prior knowledge that the widow was to be murdered and her body dumped or that he had any involvement.
November 2013: One of Mrs McConville's children tells the BBC's investigation programme Spotlight that she knows a number of the people who helped abduct her mother.
In another documentary, The Disappeared, Mr Adams is asked about allegations he had knowledge of her murder, which he strongly denies.
March 2014: Veteran republican Ivor Bell (77) is charged in connection with IRA membership, and aiding and abetting the murder of Mrs McConville following his arrest last Tuesday.
The PSNI seeks to question the former IRA man turned journalist, Anthony McIntyre, about his Boston College interviews with ex-provisionals on Mrs McConville's murder.
How story of Boston tapes has unfolded
Q Who conducted the interviews for the Belfast Project oral history project at Boston College?
AVeteran journalist and author Ed Moloney was the project director. Dr Anthony McIntyre conducted the republican interviews while Wilson McArthur spoke to former loyalist paramilitaries.
QWho was interviewed as part of the taped project?
ABoston College interviewed former paramilitaries about the Troubles on the understanding that transcripts would not be published until after their deaths. However, a US court last year ordered that tapes which mention Jean McConville be handed over to the PSNI.
QHow many people were interviewed?
AForty-six people gave recorded interviews detailing their involvement in terrorist violence to the project.
QHow were interviewees' identities protected?
AThey were all given code names. The PSNI has employed voice analysis technology in their efforts to link the interviews to known republicans.
QWhat tapes have been released following the deaths of interviewees?
AThe first to die was IRA member Brendan Hughes, who admitted taking part in the murder of Jean McConville. Brendan and deceased IRA member Dolours Price, whose recording was also handed over to the PSNI, accused Sinn Fein president Gerry Adams of ordering Jean McConville's murder.
QAnd what will happen now?
AEd Moloney, Dr Anthony McIntyre and Wilson McArthur are planning to sue Boston College after it emerged the institution didn't check its procedures on when controversial material would be published with its lawyers.