Gardai have arrested a male in his 50s in relation to the abduction and assault on businessman Kevin Lunney.
He is currently being detained at Cavan Garda station under section 50 of the criminal justice act.
In September, Quinn Industrial Holdings (QIH) director Mr Lunney, 50, was abducted outside his home near Derrylin, Co Fermanagh and taken to a horsebox across the border, where he was savagely beaten.
His attackers broke his leg, sliced his fingernails and face with a Stanley knife, carved QIH on his chest, and doused the father of six in bleach.
The attack was the most serious in a six-year campaign of intimidation targeting the companies and directors that now control the business portfolio which was built up by fallen tycoon Sean Quinn, once Ireland’s richest man.
The Quinn family has repeatedly condemned the intimidation.
The Garda and PSNI established a joint investigation team to work on the case last November.
A serial criminal considered a key suspect in the kidnapping and torture died from a heart attack when police arrested him in Buxton, Derbyshire, last November.
Cyril McGuinness, known as Dublin Jimmy, was believed to have been hiding out in the area following the assault.
In December, four men were remanded in custody at a court in Co Cavan charged with the kidnap and torture of Mr Lunney.