Former "Real IRA" leader Michael McKevitt chose not to attend his mother's funeral today after rejecting the terms of leave offered to him by the Prison Service.
His 86-year-old mother Ellen died earlier this week after a long illness and was buried today in Dundalk, Co Louth.
But the 53-year-old dissident republican shunned the service despite seeking temporary leave from prison chiefs.
McKevitt is serving a 20-year jail term at Portlaoise prison after being convicted of directing terrorism last August.
A Prison Service spokesman said: "We did try to facilitate him but he rejected the terms we offered which would have allowed him to attend the service and subsequent burial," he said. "At the end of the day we have to be aware of the nature of the offence and security concerns."
Around 100 mourners attended the Requiem Mass at St Nicholas Church. At each door of the church at least three heavily-built men kept a careful eye on proceedings.
McKevitt was granted compassionate leave to visit his dying mother last month.
He is one of five people being sued for €14 million in a landmark civil action by relatives of the 29 who were killed in the 1998 Omagh bombings. Solicitors acting for the Omagh Victim Civil Action Group served writs on the five suspects in 2002.
FBI agent David Rupert, whose testimony was central to the prosecution case at the Special Criminal Court trial, is expected to testify against McKevitt when the is heard at Belfast High Court at the beginning of next year.