A Co Donegal Fine Gael councillor, Barry O’Neill, has received a Mass card with what gardaí said was “an unpleasant message” at his home in Ballyshannon.
It is believed to be linked to the recent burning of a house in the county which had been intended to house Travellers.
A man was yesterday questioned by gardaí about the package delivered a day after the fire.
Gardaí believe arsonists were behind the attack on Monday that gutted a house into which a family of 13 Travellers were preparing to move.
The family was allocated the house by Donegal County Council despite public protests that they were being placed among a community of settled, mainly retired, people.
Three weeks ago councillors fumed at the plan by council officials to place the family in a five-bedroom house on a hilltop overlooking a scenic view at Parkhill, less than 2km outside Ballyshannon.
Gardaí are already investigating a complaint from the Donegal Travellers Project that two councillors incited hatred in public comments they made about the allocation of the house to the Travellers by the council.
Mr O’Neill, a Donegal county councillor and also an RTÉ radio sports producer, is not one of the councillors who is under investigation.