Three people have been arrested by gardaí in connection with the abduction of Quinn Industrial Holdings executive Kevin Lunney in Derrylin, Co Fermanagh.
The businessman was found with serious injuries after being taken from outside his home and then dumped by a roadside across the border in Cornafean, Co Cavan.
He had suffered knife wounds to his face and neck and had one of his legs broken in two places.
On Thursday, gardaí said they had detained a man in his 20s and a man in his 40s under Section 50 of the Criminal Justice Act 2007.
A woman in her 50s has also been arrested, under Section 30 of the Offences Against the State Act.
A spokesperson said: “An Garda Síochána continues to appeal to any person who has any information, no matter how insignificant it appears, on this vicious criminal attack, or any other criminal activities which have taken place in the Cavan/Fermanagh border area over recent years to contact us.”
A number of threats have been made against directors of Quinn Industrial Holdings.
There have been around 70 incidents throughout a five-year campaign of violence and intimidation directed at those running the company since the fall of Sean Quinn - once Ireland’s richest man.