A man in his 30s who had been arrested in relation to the abduction and assault of Kevin Lunney has been released without charge.
A file will now be prepared for the Director of Public Prosecutions.
Mr Lunney, a director of Quinn Industrial Holdings, was on his way home from work when he was abducted and severely beaten on 17 September.
Gardaí and the PSNI established a joint investigation team to work on the case last November.
Four other men have been charged in relation to that attack and are before the courts.
