Tadg O’Sullivan, 59, and his youngest son, Diarmuid, 23, planned to shoot Mark, 25 — Tadgh’s eldest son — dead, The Sun reported. The trio was found dead on their farm in Ireland on Monday, October 26.
The outlet reported that Tadg and Diarmuid shot Mark with seven bullets from their rifles, and then walked to a nearby field to kill themselves. Prior to their deaths, Tadg asked a man he worked with about a murder-suicide that happened within his own family. "This man’s family suffered a terrible tragedy in a murder-suicide incident. He said people did not did not tend to bring it up to him — but on at least three occasions, Tadg did," an acquaintance of Tadgh’s said. "He wanted to know about the emotional impact it had on the family and how they coped afterwards."
The dad and son went through with the horrendous act "to inflict as much heartbreak and sorrow" on Tadg’s wife, Anne O'Sullivan, a source said. Anne was "a very ill woman who was trying to do the best she could for her family."
The heartbreaking tragedy occurred after Tadg and Diarmuid and Mark and Anne had a big fight after she revealed she was going to leave the 150-acre farm — which she inherited — to her eldest son.
Investigators found a note written by Mark — who was a lawyer — in his mom’s medicine bag, which predicted his untimely death. He wrote that his dad and brother were going to kill him and then themselves.
"It is possible he might have overheard them talking about what they would do because they were so upset over the farm being left to him," a source said. "But it is also possible because of his legal training he may have written down the plans with a view to having them on record should be there future legal action over a will and inheritance.
"Investigators were shocked by the detail in it, which corresponded with the events which unfolded," the insider added.
Anne — who is a nurse — recently underwent surgery in Dublin, and Mark brought her to a friend’s home to rest and recover. Anne had been seriously ill, and as a result, she wanted to get her affairs in order and make sure Mark was set for the future. The duo returned to their farm on Sunday, October 25 — just one day before the three men were found dead.
Diarmuid left a 12-page suicide note for his mother, where he complained about his older brother.
Mark was shot around 6:30 a.m. on October 26, while Diarmuid and Tadgh’s bodies were found near the home. Anne heard the gunshots and saw her husband and Diarmuid with weapons at Mark's door. Anne then escaped the house, according to several reports, and tried to call the police, but her husband and son caught up to her in the yard and took her phone and smashed it.
Tadgh or Diarmuid said to Anne, "I hope you think the land is worth it now," The Irish Times reported, before telling her that they were going to take their own lives. Anne ran to a neighbor's home to call the police, who immediately responded.