Veteran republican Marian Price has said she "vehemently denies" allegations contained in a new book that link her to the 1972 murder of Jean McConville.
New York Times journalist Patrick Radden Keefe claims in Say Nothing that Price was the mystery third member of an IRA team that shot dead Mrs McConville, one of the highest-profile victims of the Troubles.
Marian Price's older sister Dolours, who died in 2013, and Brendan Hughes, who died in 2008, both previously gave interviews to Boston College project director Ed Moloney, copies of which were later passed to the PSNI following a lengthy court battle.
Dolours Price had admitted being part of the three-person IRA squad involved in the murder of Mrs McConville.
That interview with journalist Mr Moloney featured in the controversial documentary film I, Dolours earlier this year.
She said they left the widow with an IRA unit in Dundalk, but were called back four or five days later to shoot her. She denied firing the fatal bullet, instead saying an unnamed member of the unit had been responsible.
Piecing together evidence from two interviews by Moloney and from a third unnamed source, the author now claims Marian Price fired the shot that killed Mrs McConville.
In his book he alleges that a member of the team had been offered a job as Gerry Adams' personal driver and that Keefe discovered Dolours Price revealed her younger sister had been offered this role "and refused because it was such a boring job".
Keefe said he also interviewed a person in whom Dolours Price confided before her death.
"I asked whether she had ever mentioned Marian playing a role in the McConville killing," he writes.
"The person confirmed she had - that Dolours had said the execution of Jean McConville was 'something sisters had done together'."
Responding to the allegations, Marian Price's solicitor Peter Corrigan of Phoenix Law told The Irish News: "My client Marian Price vehemently denies any involvement in the murder of Jean McConville.
"She outright refutes any assertion to the contrary. We have now been instructed to review the publication in question, and the appropriate action will follow if necessary."
In the book the author recalls that when Dolours Price died in 2013 Marian Price, who was in prison, wanted to be released for the wake and the funeral.
She was allowed to attend the wake.
He read the court papers where her lawyers and a psychiatrist made the valid argument that "when you lose a family member you really need to properly grieve".
Keefe notes that the McConville family did not know what happened their mother until her body was found in Shelling Hill beach, Co Louth, in 2003.
He also claims that police have known since 2013 that, according to her Dolours Price, Marian Price was alleged to have been involved in the murder.
Mrs McConville's son Michael called that "awful and shocking" and has asked for a face to face meeting with PSNI Chief Constable George Hamilton.
"My brothers and sisters and I want to know why Dolours Price was not interviewed after her admissions that she drove my mother to her death?" he said.
"And if Marian Price has been interviewed by the PSNI why have we not been informed, and if she hasn't been interviewed from 2013 to the present day, why not?"