Liam Adams, 58, younger brother of Sinn Fein president Gerry Adams, has been found guilty of raping and sexually assaulting his daughter Aine over a six-year period between 1977 and 1983 when she was aged between four and nine.
Gerry Adams had testified against his brother in a first trial that had collapsed but was not called as a witness in the second trial.
A jury of nine men and three women heard more than two weeks of evidence at Belfast Crown Court and took almost four hours to reach their verdict this week. Adams reportedly showed no emotion as the guilty verdict was returned.
The victim in the case, Aine Adams, 40, waived her right to anonymity to attend the trial. She was there to hear the jury foreman read out guilty verdicts on all of the 10 charges to the packed court.
Liam Adams, who now walks with the aid of a stick and reportedly used a hearing aid to follow proceedings, stood between two prison officers as the verdicts were read out.
According to the Belfast Telegraph Aine Adams wept and clutched her younger sister Sinead for support when the verdicts were announced. Liam Adams's second wife Bronagh and their daughter Claire, who both gave evidence in his defence, were in the courtroom and also reportedly cried.
During the trial Aine Adams gave shocking details of the abuse, which she said started when she was aged four.
The first time she recalled being raped was while her mother was in hospital giving birth to her younger brother Conor in 1977. In another incident she was raped by her father at a flat on Belfast's Antrim Road while her brother was asleep in the bed beside her.
Adams, who was allegedly a heavy drinker, also forced his daughter to perform sex acts.
In a statement Aine Adams said she could finally begin to move on after achieving justice.
'I do not see this verdict as a victory or a celebration as it has taken its toll and has caused hurt, heartache and anguish for all those involved. I can now begin my life at 40 and lay to rest the memory of the five-year-old girl who was abused,' she said.
The allegations were first made against her father when she took part in a television documentary in 2009. A short time after it broadcast, Gerry Adams revealed his own father Gerry Snr, a veteran IRA man, had physically and sexually abused members of his family.
Within days of the documentary being broadcast Liam Adams fled to the Republic claiming he would not receive a fair trial in Northern Ireland. At the time he reportedly handed himself in to police in County Sligo but they failed to detain him because the police officers did not have the correct documentation.
Adams was finally handed over to the Police Service of Northern Ireland (PSNI) in November 2011 after losing a long extradition battle.
In her public statement Aine Adams thanked the media for helping her to tell her story. 'I would like to give all my family a special thanks. Without their love, support and understanding I would not be here today.'
Adams also expressed her gratitude to the PSNI's public protection unit and the Public Prosecution Service.
'I would now ask for some privacy for my family to reflect on recent trying times,' she said. Adams is due to be sentenced next month.