A man has been arrested in relation to the murder of Sinn Féin councillor Eddie Fullerton.
The former Donegal councillor was shot dead at his home in Buncrana by members of the Ulster Defence Association on May 25th, 1991.
Gardaí from the Donegal Division arrested a 56-year-old man on Sunday morning.
He is currently being detained at Letterkenny garda station under Section 30 of the Offences Against the State Act.
Gardaí said that anyone with information in relation to the murder should contact the Garda Confidential Line on 1800 666 111.
Fullerton was the first Sinn Féin member to be elected to Donegal County Council in 1979.
His biggest political achievement was the building of a dam and reservoir in Inishowen, which was named after him.
His family, along with Sinn Féin, have repeatedly called for an independent inquiry into his death, alleging that there was collusion between loyalist paramilitaries and British security forces.