Monday is the 39th anniversary of the Kingsmill massacre in south Armagh when 10 Protestant workmen were murdered.
The atrocity, on Monday January 5, 1976, is regarded as among the most heinous in the Troubles, and still no one has been apprehended for the killings.
This morning families of the victims will lay wreaths at the memorial site on the Kingsmill Road, about three miles from Bessbrook where most of the workmen lived.
A short service of remembrance will involve the families, and wreaths will also be laid at the Kingsmills memorial in Bessbrook village.
There were 12 people on the workmen’s minibus – Alan Black, a Protestant, survived serious bullet wounds, while a Roman Catholic man was allowed to go free.
The 10 who died were: Joseph Lemmon, James McWhirter, John Bryans, John McConville, Reggie Chapman, Walter Chapman, Robert Freeburn, Robert Walker, Robert Chambers and Kenneth Worton.
Preliminary inquest hearings into the killings – claimed by the so-called “South Armagh Republican Action Force” – began last year.