Former Real IRA leader Michael McKevitt has died following a battle with cancer.
McKevitt, who was one of four men found liable for the Omagh bomb, had been diagnosed with terminal cancer a number of years ago.
He was released from prison in 2016 after serving a 20-year sentence for directing terrorism and membership of an illegal organisation.
The 71-year-old was married to Bernadette Sands McKevitt, a sister of IRA hunger striker Bobby Sands.
From Co Louth, McKevitt always denied being involved in the 1998 Omagh bombing, but in 2009 a judge ruled in a landmark civil trial that McKevitt, Liam Campbell, Colm Murphy and Seamus Daly were all liable for the bomb.
He ordered them to pay a total of £1.6 million damages to 12 relatives who took the case.
A fifth man, Seamus McKenna, was cleared of liability for the bombing.
No-one has ever been convicted of the dissident republican bomb attack in Omagh which killed 29 people, including a woman pregnant with twins.
In 2019, McKevitt was adjudicated bankrupt in the High Court following failure to pay out the damages.