A man aged in his 50s has been released without charge in connection with the abduction and assault on Kevin Lunney last September.
A file is to be prepared for the Director of Public Prosecutions (DPP).
Four men are before the courts charged with a number of offences in relation to the kidnap and assault on the Quinn Industrial Holdings executive.
A further four people were arrested last week and released without charge.
Mr Lunney was driving from work to his home in Kinawley, Co Fermanagh when he was attacked on September 17th last.
He described how he was beaten and tortured by three men in an attack that lasted for about two and a half hours.
He also said he had the letters 'QIH' cut into his chest with a Stanley knife.