Gerry Adams has been forced to deny involvement in Jean McConville's murder for years.
But a court decision in the US has now compelled the Sinn Fein president to make those same denials to detectives investigating the mother-of-10's abduction, killing and secret burial by the IRA.
In 2001 Boston College commenced a five-year oral history project aimed at documenting perspectives on the Troubles from those involved in the conflict.
Academics, historians and journalists interviewed former paramilitaries, both republican and loyalist, about their roles in the 40 years of violence that blighted Northern Ireland.
The participants took part on the undertaking that their accounts would only be made public upon their death.
When one such interviewee, former IRA commander in Belfast Brendan Hughes, died in 2008 it emerged that on the tapes he alleged Mr Adams was a senior IRA leader during the Troubles and had ordered Mrs McConville's killing - claims the Sinn Fein leader vehemently contested.
Prior to her death last year, Old Bailey bomber Dolours Price made it public that she had also given an interview to Boston College about Mrs McConville's death in which she made similar allegations about Mr Adams. Again the Louth TD rejected the claims.
The revelations prompted lawyers representing the PSNI to launch a legal bid in the US to obtain the Boston College tapes that touched on Mrs McConville's death.
A long court battle ensued but last year the PSNI won and the college was ordered to pass over the tapes.
Having taken time to examine their contents, detectives ramped up their investigation in the last two months, making a series of arrests.
In March veteran republican Ivor Bell, 77, from Ramoan Gardens in the Andersonstown district of west Belfast, was charged with aiding and abetting in the murder - a counts he denies.
Five others have been detained and questioned by detectives.
But the latest arrest is undeniably the most high profile to date.