A man left a note to his mum predicting he would be killed by his dad and brother before they shot him and then themselves.

Mark O'Sullivan, 25, was found dead at the family farm in Kanturk, Cork, on Monday, with the bodies of his father Tadhg, 59, and his brother Diarmuid, 23, discovered in a nearby field.

Tadhg and Diarmund planned to confront Mark in his bedroom knowing he couldn't escape, where it is understood multiple shots were fired.

He was shot seven times, with a number of them thought to be fatal.

Following the deaths it emerged that the eldest son left a note which was found in his mum Ann's medicine bag, The Sun reported.

Father Tadgh, son Mark and wife Ann O’Sullivan

In it he explained how he feared Tadhg and Diarmund were planning to kill him and then themselves.

A source is reported to have told the publication: “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.

“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 there be future legal action over a will and inheritance.”

Gardai are investigating whether the younger son, who was to be conferred with his honours degree in accounting in Cork Institute of Technology next week, and his mechanic dad planned the killing together.

Mark at his graduation last March with his mother Ann
Diarmuid O'Sullivan was found dead in the field

Tadgh and Diarmuid both sustained a single gunshot wound inflicted at close range in a field 600 metres away from the farmhouse.

The shots Mark sustained were fired by the guns used by Tadgh and Diarmuid.

The triple shooting followed escalated tensions within the family after a proposed will was written which was seen to favour Mark with a farm inheritance, Independant.ie reports.

Diarmuid was said to be deeply upset over the proposed terms of the will.

Mark on his graduation with his father Tadhg

It comes as it was revealed that a 12-page-note was found on Diarmuid's body.

It outlined his anguish at the inheritance dispute and the toll it had taken on him and their family.

Gardai recovered three legally held shotguns and rifles at the scene.

The note has been described as 'lengthy and detailed.'

While detectives are treating the matter as a criminal investigation, they are not looking for anyone else in connection with the incident.

A view of the farmhouse in Assolas where the three bodies were found
Father John Magner of Kanturk Parish prayed with the boys' mother

Ann, a 60-year-old nurse based in nearby Mallow, had been battling serious health issues prior to the deaths.

Father John Magner said the community where the two brothers died with their father in the shootings has been left “numbed, stunned and devastated” by the tragedy.

He prayed with the boys' mother as he described her heartbreak.

“There are no words,” he said.

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