DUP councillor Ruth Patterson has been arrested over comments she posted on Facebook about an imagined attack on a republican parade.
Ruth Patterson, 57, a member of Northern Ireland First Minister Peter Robinson's Democratic Unionist Party, was detained by police on Friday in relation to offences concerning the sending of grossly offensive communications and other serious criminal offences in relation to intimidation and encouraging criminal acts.
The unionist councillor for Balmoral is alleged to have made the comments in a conversation on Facebook about the controversial parade planned for Castlederg on August 11.
The DUP has confirmed it was councillor Ruth Patterson who was arrested.
The Facebook page has now been deleted and she has apologised for a "lapse in judgement".
The contentious republican parade is planned for August 11 in Castlederg, to mark the deaths of two IRA men who blew themselves up with their own bomb.
The parade has sparked a huge political row between Sinn Fein and the DUP, with unionist politicians describing the event as "obnoxious" and a "parade of shame".
Peter Robinson has hit out at the decision to hold the annual Tyrone Volunteers Day parade in Castlederg - the town the bombers had been targeting - rather than where they died.