The man, in his 50s, was released after being questioned by the Garda for two days following his arrest in Dundalk, Co Louth.
Mr Quinn, from south Armagh, was lured across the border and beaten to death at farm buildings near Castleblayney, Co Monaghan last October.
Eleven people have been questioned by both the Gardaí and the PSNI in recent months but none charged.
The Quinn family insist IRA members killed the 21-year-old after he had defied an order to leave the country.
Sinn Féin has constantly denied any republican involvement.
