Old Bailey bomber Dolours Price has been found dead at her home in Dublin.
The 62-year-old mother-of-two was found at her home in Malahide last night, sources said.
Price, the former wife of actor Stephen Rea, was a convicted Provisional IRA car bomber for the 1973 attack on London's Old Bailey courts in which one man died and more than 200 people were injured.
A Garda spokesman said officers were investigating the sudden death of a woman at a home on St Margaret's Road in Malahide at around 10pm last night.
Her death is not being treated as suspicious. A postmortem is due to take place on her body at the Connolly Hospital Blanchardstown later today.
Ms Price and her 58-year-old sister Marian, who has been imprisoned in Northern Ireland since 2011 after her licence was revoked after she read a statement at a dissident republican Easter Rising commemoration in Derry, were vocal critics of the peace process.
The two sisters were part of the IRA unit that planted four car bombs outside the Old Bailey in 1973. Two of the bombs exploded. More than 200 people were injured, some seriously. One man died from a heart attack.
The sisters went on hunger strike after being charged over the attack. They refused food for 200 days and were subsequently repatriated to Northern Ireland to serve their life sentences.
Dolours Price had accused Sinn Féin president Gerry Adams of sanctioning the Old Bailey attack. She also alleged that he personally ordered the abduction of several people the IRA considered to be traitors in the 1970s, including Jean McConville.
Mr Adams has always denied ever being a member of the IRA.
Ms Price claimed she made the allegations on the record to researchers working for Boston College in the US, which the PSNI has been battling to recover as evidence. The recordings were made on the basis that they remain secret until the death of the 28 former IRA and Ulster Volunteer Force members who took part.
Speaking outside Leinster House this afternoon, Mr Adams said he was shocked by Ms Price's death and insisted he feels no bitterness towards her.
"None whatsoever," he said. "I'm sad and shocked to hear that she is dead, and I'm sure everybody who knew her or knew of her will also be sad at this time."
He also called for the release of Marian Price from prison, adding that she should never have been jailed without a trial. Mr Adams said both sisters were extremely close, having spent time in prison together, and that Dolours' death would be particularly hard on Marian. He said both women had lived hard lives as a result of their involvement in what he called "the civil rights struggle".
"Dolours had a very tough life, like many people," he said. "She was a long time imprisoned in England. She endured over 200 days of force feeding while on hunger strike. She had many trials and tribulations in her life."
Mr Adams, who said he had not spoken to Dolours Price for some time, said he had no concerns about her allegations against him being made public by Boston College. "I never worry about matters that I have no control over and I have no concerns about any of those issues because they are not true," he said.
PA