Police in the Republic of Ireland will have to question Gerry Adams if secret IRA tapes held in the US are handed over to the authorities in Northern Ireland, the family of murdered Jean McConville has claimed.
Relatives of the mother of 10 have said the onus will eventually be on gardai to question the Sinn Fein president over her kidnapping, disappearance and murder back in 1972.
Ex-IRA members including the late Brendan 'Darkie' Hughes have claimed Mr Adams gave the order for Ms McConville to be "disappeared" after being murdered. She was branded an informer, a claim which has been disputed by her family for four decades
The US Supreme Court is to rule this autumn on whether tape recordings of IRA activists held by Boston College can be handed over to the Police Service of Northern Ireland.
The PSNI wants to obtain recorded material in the college's archive that relates to Ms McConville's murder.
The PSNI is now only one step away from seizing the tapes that could prove highly damaging to Mr Adams's claim that he was never a member or active inside the IRA.
Journalists and academics who set up the archive known as the "Belfast Project" have campaigned on both sides of the Atlantic to prevent the tapes being seized.
The daughter and son-in-law of the murdered widow believe the buck will ultimately stop with the gardai if the PSNI wins the legal battle.
They point out that her remains were found on Templetown beach in Mr Adams's Louth constituency, and that all the evidence shows she was murdered in the jurisdiction.
Seamus McKendry wrote a book on his mother-in-law's disappearance and the search for her remains.
He said the family has also been told by security sources that the fatal shots were fired into Ms McConville's body in Louth once she had been smuggled across the border from Belfast.
"I sat through every single day of Jean's inquest and it was quite clear to me that the murder weapon was fired in and around that area.
"The forensic evidence from the inquest points to that. The crime was committed in the Republic of Ireland so the onus is on the gardai to conduct the inquiry and that means it is they who will have to arrest and question Adams about what he knew relating to Jean's disappearance.
"I accept that this will be politically explosive but justice must be seen to be done. It doesn't matter if he is a member of the Dail or not.
"Eventually, if the United States holds firm and gives those tapes to the PSNI, the gardai will have to come on board."
Mr McKendry and his wife Helen, who was 14 when her mother was dragged away from the family home in front of her screaming, terrified siblings, called on the US authorities to resist demands that the tapes remain in Boston.
"These tapes contain important information about what happened to Jean so there is a duty to hand them over," the couple said.
Louth TD and Sinn Fein chief Mr Adams has repeatedly denied claims by his former friend and fellow Long Kesh prisoner Brendan Hughes that he ordered Jean McConville's murder.
Last week, Northern Ireland Deputy First Minister Martin McGuinness claimed in the US that the Boston College tapes could be used to destabilise progress in Northern Ireland.
Source Irish Independent