Four young women were murdered across four decades in Ireland's Badlands. Four murderers, one of them dead, the other three still at large, none of them ever having faced trial for their horrific actions.
In 1973, the body of 18 year old Marian Beattie was found at the foot of a cliff in a quarry up a narrow country road.
In 1988, the body of 18 year old German backpacker, Inga Maria Hauser was found at the end of a dark track within the most remote part of a forest.
Fifteen year old Arlene Arkinson disappeared in 1994. Her remains are undiscovered, but are presumed to have been buried in one of the vast swathes of bogland or forestry on the Irish Border.
Lisa Dorrian, who was 25, vanished in 2005. Her body is also missing, but it may well be hidden in some isolated spot somewhere within a disused second world war airfield. Or it may be in the Irish Sea.