A brother of prominent Northern Irish politician Gerry Adams was sentenced on Wednesday to 16 years in prison for raping his daughter when she was a child.

Liam Adams, 58, was convicted in April of 10 charges of rape and sexual abuse dating back more than 30 years against his eldest child, Aine Dahlstrom, who waived her right to anonymity. He had denied all charges.

Judge Corinne Philpott said Liam Adams was guilty of the "greatest imaginable breach of trust."

Gerry Adams, president of the nationalist Sinn Fein party, was for years the face of republican opposition to British rule in Northern Ireland and was once interned as a guerrilla suspect.

He has dissociated himself from his brother since the allegations but has faced questions about what and when he knew of the abuse of his niece.

Unionist politicians questioned Gerry Adams's silence

The Northern Ireland Attorney General is currently reviewing a Public Prosecution Service decision not to prosecute Gerry Adams over allegations of withholding information from the police on the issue.

Gerry-Adams

Gerry Adams, the leader of the Irish nationalist Sinn Fein party and long the face of the Republican cause, has been accused of not reporting his brother's abuse against his niece when he first learned of it in the 1980s. (Peter Morrison/Associated Press)

The police ombudsman has also begun an investigation into the Adams case and the police decision not to take action against the Sinn Fein president. It launched the probe after a complaint from unionist politicians opposed to Sinn Fein.

Liam Adams fled across the border to the Irish Republic after Aine made the allegations in 1987 and was extradited to Northern Ireland in 2011.

His daughter told the trial the sexual abuse took place between 1977 and 1983 and started when she was five and her mother was in hospital giving birth to her younger brother.

Aine said she first made allegations against her father in 1987 but later withdrew them because the police at the time seemed more interested in gathering information against her uncle Gerry.