When Anne O'Sullivan was diagnosed with terminal cancer, tensions within her family about who would inherit her substantial plot of farm land came to the surface.

Soon, Anne would find herself awake before dawn, running through fields and ditches to a neighbour's house to get help as a terrible darkness descended on the family farm.

This is a tragic story that saw a family torn apart as their home became consumed by fear and threats of violence towards Anne and her eldest son, Mark. Those rising tensions would lead to the most unfathomable and shocking moment of hatred and rage.

In this episode of Lines of Enquiry, John tracks the descent into violence and revisits his case notes on the letters that proved crucial to any understanding of events of that tragic day.

Presented by John Sweetman

Created by Darren Cleary

Episode Written by Eoin Brennan

Script Edited by John Sweetman

Research by Siobhan Maguire & Eoin Brennan

Executive Produced by Eoin Brennan

Executive Produced by Ruth Fitzsimons

Produced by Siobhan Walsh

Produced by Siobhan Maguire

Sound Design and Editing by Neil Kavanagh

Audio Editing Support by Ed Smith

Marketing Support by Bríd Walsh and Róisín Reilly

Social Support by Mark Hayes and Robyn Ree

Artwork and Graphics by Eric Rowntree